221997024 has 72 divisors (see below), whose sum is σ = 654708600. Its totient is φ = 73996416.

The previous prime is 221997011. The next prime is 221997079. The reversal of 221997024 is 420799122.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a self number, because there is not a number n which added to its sum of digits gives 221997024.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6499 + ... + 22050.

It is an arithmetic number, because the mean of its divisors is an integer number (9093175).

Almost surely, 2^221997024 is an apocalyptic number.

221997024 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

221997024 is an abundant number, since it is smaller than the sum of its proper divisors (432711576).

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

221997024 is an equidigital number, since it uses as much as digits as its factorization.

221997024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28574 (or 28554 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 221997024 is about 14899.5645573956. The cubic root of 221997024 is about 605.5021889595.

The spelling of 221997024 in words is "two hundred twenty-one million, nine hundred ninety-seven thousand, twenty-four".