64631961 has 12 divisors (see below), whose sum is σ = 93602340. Its totient is φ = 42974880.

The previous prime is 64631953. The next prime is 64631971. The reversal of 64631961 is 16913646.

64631961 is a `hidden beast` number, since 6 + 463 + 196 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 8156736 + 56475225 = 2856^2 + 7515^2 .

It is not a de Polignac number, because 64631961 - 2³ = 64631953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64631911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5730 + ... + 12731.

It is an arithmetic number, because the mean of its divisors is an integer number (7800195).

Almost surely, 2^64631961 is an apocalyptic number.

It is an amenable number.

64631961 is a deficient number, since it is larger than the sum of its proper divisors (28970379).

64631961 is a wasteful number, since it uses less digits than its factorization.

64631961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18856 (or 18853 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 64631961 is about 8039.4005373535. The cubic root of 64631961 is about 401.3122755410.

It can be divided in two parts, 64 and 631961, that added together give a square (632025 = 795²).

The spelling of 64631961 in words is "sixty-four million, six hundred thirty-one thousand, nine hundred sixty-one".