621631021 has 16 divisors (see below), whose sum is σ = 693619200. Its totient is φ = 552334000.

The previous prime is 621631019. The next prime is 621631067. The reversal of 621631021 is 120136126.

It is a cyclic number.

It is not a de Polignac number, because 621631021 - 2¹ = 621631019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 621630983 and 621631001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621631081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 113496 + ... + 118846.

It is an arithmetic number, because the mean of its divisors is an integer number (43351200).

Almost surely, 2^621631021 is an apocalyptic number.

It is an amenable number.

621631021 is a deficient number, since it is larger than the sum of its proper divisors (71988179).

621631021 is a wasteful number, since it uses less digits than its factorization.

621631021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5600.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 621631021 is about 24932.5293742933. The cubic root of 621631021 is about 853.4489719419.

Adding to 621631021 its reverse (120136126), we get a palindrome (741767147).

The spelling of 621631021 in words is "six hundred twenty-one million, six hundred thirty-one thousand, twenty-one".