64691657 has 2 divisors, whose sum is σ = 64691658. Its totient is φ = 64691656.

The previous prime is 64691639. The next prime is 64691689. The reversal of 64691657 is 75619646.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64336441 + 355216 = 8021^2 + 596^2 .

It is a cyclic number.

It is not a de Polignac number, because 64691657 - 2⁶ = 64691593 is a prime.

It is a super-4 number, since 4×64691657⁴ (a number of 32 digits) contains 4444 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64691357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32345828 + 32345829.

It is an arithmetic number, because the mean of its divisors is an integer number (32345829).

Almost surely, 2^64691657 is an apocalyptic number.

It is an amenable number.

64691657 is a deficient number, since it is larger than the sum of its proper divisors (1).

64691657 is an equidigital number, since it uses as much as digits as its factorization.

64691657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 272160, while the sum is 44.

The square root of 64691657 is about 8043.1123950869. The cubic root of 64691657 is about 401.4357921690.

The spelling of 64691657 in words is "sixty-four million, six hundred ninety-one thousand, six hundred fifty-seven".