64656881 has 2 divisors, whose sum is σ = 64656882. Its totient is φ = 64656880.

The previous prime is 64656853. The next prime is 64656901. The reversal of 64656881 is 18865646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57896881 + 6760000 = 7609^2 + 2600^2 .

It is a cyclic number.

It is not a de Polignac number, because 64656881 - 2¹⁴ = 64640497 is a prime.

It is a super-2 number, since 2×64656881² = 8361024521296322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64656281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32328440 + 32328441.

It is an arithmetic number, because the mean of its divisors is an integer number (32328441).

Almost surely, 2^64656881 is an apocalyptic number.

It is an amenable number.

64656881 is a deficient number, since it is larger than the sum of its proper divisors (1).

64656881 is an equidigital number, since it uses as much as digits as its factorization.

64656881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 276480, while the sum is 44.

The square root of 64656881 is about 8040.9502547895. The cubic root of 64656881 is about 401.3638466043.

The spelling of 64656881 in words is "sixty-four million, six hundred fifty-six thousand, eight hundred eighty-one".