64891356641 has 2 divisors, whose sum is σ = 64891356642. Its totient is φ = 64891356640.

The previous prime is 64891356611. The next prime is 64891356653. The reversal of 64891356641 is 14665319846.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64454546641 + 436810000 = 253879^2 + 20900^2 .

It is a cyclic number.

It is not a de Polignac number, because 64891356641 - 2²² = 64887162337 is a prime.

It is not a weakly prime, because it can be changed into another prime (64891356611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32445678320 + 32445678321.

It is an arithmetic number, because the mean of its divisors is an integer number (32445678321).

Almost surely, 2^64891356641 is an apocalyptic number.

It is an amenable number.

64891356641 is a deficient number, since it is larger than the sum of its proper divisors (1).

64891356641 is an equidigital number, since it uses as much as digits as its factorization.

64891356641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3732480, while the sum is 53.

The spelling of 64891356641 in words is "sixty-four billion, eight hundred ninety-one million, three hundred fifty-six thousand, six hundred forty-one".