626619989 has 2 divisors, whose sum is σ = 626619990. Its totient is φ = 626619988.

The previous prime is 626619977. The next prime is 626619991. The reversal of 626619989 is 989916626.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 584914225 + 41705764 = 24185^2 + 6458^2 .

It is a cyclic number.

It is not a de Polignac number, because 626619989 - 2¹² = 626615893 is a prime.

It is a super-2 number, since 2×626619989² = 785305221228720242, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 626619991, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (626619919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 313309994 + 313309995.

It is an arithmetic number, because the mean of its divisors is an integer number (313309995).

Almost surely, 2^626619989 is an apocalyptic number.

It is an amenable number.

626619989 is a deficient number, since it is larger than the sum of its proper divisors (1).

626619989 is an equidigital number, since it uses as much as digits as its factorization.

626619989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2519424, while the sum is 56.

The square root of 626619989 is about 25032.3788122503. The cubic root of 626619989 is about 855.7260406124.

The spelling of 626619989 in words is "six hundred twenty-six million, six hundred nineteen thousand, nine hundred eighty-nine".