626863981 has 2 divisors, whose sum is σ = 626863982. Its totient is φ = 626863980.

The previous prime is 626863889. The next prime is 626864023. The reversal of 626863981 is 189368626.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 611770756 + 15093225 = 24734^2 + 3885^2 .

It is a cyclic number.

It is not a de Polignac number, because 626863981 - 2¹¹ = 626861933 is a prime.

It is a super-2 number, since 2×626863981² = 785916901350336722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (626861981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 313431990 + 313431991.

It is an arithmetic number, because the mean of its divisors is an integer number (313431991).

Almost surely, 2^626863981 is an apocalyptic number.

It is an amenable number.

626863981 is a deficient number, since it is larger than the sum of its proper divisors (1).

626863981 is an equidigital number, since it uses as much as digits as its factorization.

626863981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 49.

The square root of 626863981 is about 25037.2518659696. The cubic root of 626863981 is about 855.8370931473.

The spelling of 626863981 in words is "six hundred twenty-six million, eight hundred sixty-three thousand, nine hundred eighty-one".