621642431 has 2 divisors, whose sum is σ = 621642432. Its totient is φ = 621642430.

The previous prime is 621642409. The next prime is 621642557. The reversal of 621642431 is 134246126.

621642431 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-621642431 is a prime.

It is a super-2 number, since 2×621642431² = 772878624039179522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 621642394 and 621642403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (621642031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310821215 + 310821216.

It is an arithmetic number, because the mean of its divisors is an integer number (310821216).

Almost surely, 2^621642431 is an apocalyptic number.

621642431 is a deficient number, since it is larger than the sum of its proper divisors (1).

621642431 is an equidigital number, since it uses as much as digits as its factorization.

621642431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 29.

The square root of 621642431 is about 24932.7581907819. The cubic root of 621642431 is about 853.4541935781.

Adding to 621642431 its reverse (134246126), we get a palindrome (755888557).

The spelling of 621642431 in words is "six hundred twenty-one million, six hundred forty-two thousand, four hundred thirty-one".