221599440 has 120 divisors (see below), whose sum is σ = 769939560. Its totient is φ = 57050112.

The previous prime is 221599429. The next prime is 221599487. The reversal of 221599440 is 44995122.

221599440 is a `hidden beast` number, since 2 + 21 + 599 + 4 + 40 = 666.

221599440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 93547584 + 128051856 = 9672^2 + 11316^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 221599395 and 221599404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15574 + ... + 26186.

It is an arithmetic number, because the mean of its divisors is an integer number (6416163).

Almost surely, 2^221599440 is an apocalyptic number.

221599440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221599440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (384969780).

221599440 is an abundant number, since it is smaller than the sum of its proper divisors (548340120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221599440 is a wasteful number, since it uses less digits than its factorization.

221599440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10661 (or 10652 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 221599440 is about 14886.2164434083. The cubic root of 221599440 is about 605.1404996643.

The spelling of 221599440 in words is "two hundred twenty-one million, five hundred ninety-nine thousand, four hundred forty".