65657681 has 2 divisors, whose sum is σ = 65657682. Its totient is φ = 65657680.

The previous prime is 65657671. The next prime is 65657693. The reversal of 65657681 is 18675656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64657681 + 1000000 = 8041^2 + 1000^2 .

It is a cyclic number.

It is not a de Polignac number, because 65657681 - 2¹⁸ = 65395537 is a prime.

It is a super-2 number, since 2×65657681² = 8621862148595522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (65657671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32828840 + 32828841.

It is an arithmetic number, because the mean of its divisors is an integer number (32828841).

Almost surely, 2^65657681 is an apocalyptic number.

It is an amenable number.

65657681 is a deficient number, since it is larger than the sum of its proper divisors (1).

65657681 is an equidigital number, since it uses as much as digits as its factorization.

65657681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 302400, while the sum is 44.

The square root of 65657681 is about 8102.9427370555. The cubic root of 65657681 is about 403.4241071711.

The spelling of 65657681 in words is "sixty-five million, six hundred fifty-seven thousand, six hundred eighty-one".