64910673981 has 6 divisors (see below), whose sum is σ = 93759862430. Its totient is φ = 43273782648.

The previous prime is 64910673977. The next prime is 64910674009. The reversal of 64910673981 is 18937601946.

64910673981 is a `hidden beast` number, since 6 + 491 + 0 + 6 + 73 + 9 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 53469162756 + 11441511225 = 231234^2 + 106965^2 .

It is not a de Polignac number, because 64910673981 - 2² = 64910673977 is a prime.

It is a super-2 number, since 2×64910673981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64910673901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3606148546 + ... + 3606148563.

Almost surely, 2^64910673981 is an apocalyptic number.

It is an amenable number.

64910673981 is a deficient number, since it is larger than the sum of its proper divisors (28849188449).

64910673981 is a wasteful number, since it uses less digits than its factorization.

64910673981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7212297115 (or 7212297112 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The spelling of 64910673981 in words is "sixty-four billion, nine hundred ten million, six hundred seventy-three thousand, nine hundred eighty-one".