221245020 has 120 divisors (see below), whose sum is σ = 711195408. Its totient is φ = 57542400.

The previous prime is 221245009. The next prime is 221245033. The reversal of 221245020 is 20542122.

221245020 is a `hidden beast` number, since 2 + 212 + 450 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 221244984 and 221245002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 64755 + ... + 68085.

Almost surely, 2^221245020 is an apocalyptic number.

221245020 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 221245020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355597704).

221245020 is an abundant number, since it is smaller than the sum of its proper divisors (489950388).

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

221245020 is a wasteful number, since it uses less digits than its factorization.

221245020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3393 (or 3382 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 221245020 is about 14874.3073788328. The cubic root of 221245020 is about 604.8177125387.

Adding to 221245020 its reverse (20542122), we get a palindrome (241787142).

The spelling of 221245020 in words is "two hundred twenty-one million, two hundred forty-five thousand, twenty".