622721521 has 4 divisors (see below), whose sum is σ = 642809344. Its totient is φ = 602633700.

The previous prime is 622721501. The next prime is 622721549. The reversal of 622721521 is 125127226.

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 622721521 - 2¹⁵ = 622688753 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 622721521.

It is not an unprimeable number, because it can be changed into a prime (622721501) 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, 10043865 + ... + 10043926.

It is an arithmetic number, because the mean of its divisors is an integer number (160702336).

Almost surely, 2^622721521 is an apocalyptic number.

It is an amenable number.

622721521 is a deficient number, since it is larger than the sum of its proper divisors (20087823).

622721521 is a wasteful number, since it uses less digits than its factorization.

622721521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20087822.

The product of its digits is 3360, while the sum is 28.

The square root of 622721521 is about 24954.3888123913. The cubic root of 622721521 is about 853.9477364188.

Adding to 622721521 its reverse (125127226), we get a palindrome (747848747).

The spelling of 622721521 in words is "six hundred twenty-two million, seven hundred twenty-one thousand, five hundred twenty-one".