626687921 has 2 divisors, whose sum is σ = 626687922. Its totient is φ = 626687920.

The previous prime is 626687903. The next prime is 626688047. The reversal of 626687921 is 129786626.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 613255696 + 13432225 = 24764^2 + 3665^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-626687921 is a prime.

It is not a weakly prime, because it can be changed into another prime (626687821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 313343960 + 313343961.

It is an arithmetic number, because the mean of its divisors is an integer number (313343961).

Almost surely, 2^626687921 is an apocalyptic number.

It is an amenable number.

626687921 is a deficient number, since it is larger than the sum of its proper divisors (1).

626687921 is an equidigital number, since it uses as much as digits as its factorization.

626687921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 47.

The square root of 626687921 is about 25033.7356581074. The cubic root of 626687921 is about 855.7569626395.

The spelling of 626687921 in words is "six hundred twenty-six million, six hundred eighty-seven thousand, nine hundred twenty-one".