72205021 has 4 divisors (see below), whose sum is σ = 82520032. Its totient is φ = 61890012.

The previous prime is 72204989. The next prime is 72205033. The reversal of 72205021 is 12050227.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72205021 - 2⁵ = 72204989 is a prime.

It is a super-2 number, since 2×72205021² = 10427130115220882, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 72205021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72205051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5157495 + ... + 5157508.

It is an arithmetic number, because the mean of its divisors is an integer number (20630008).

Almost surely, 2^72205021 is an apocalyptic number.

It is an amenable number.

72205021 is a deficient number, since it is larger than the sum of its proper divisors (10315011).

72205021 is a wasteful number, since it uses less digits than its factorization.

72205021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10315010.

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 72205021 is about 8497.3537645552. The cubic root of 72205021 is about 416.4112615735.

Adding to 72205021 its reverse (12050227), we get a palindrome (84255248).

The spelling of 72205021 in words is "seventy-two million, two hundred five thousand, twenty-one".