64728531 has 32 divisors (see below), whose sum is σ = 110208000. Its totient is φ = 36780480.

The previous prime is 64728523. The next prime is 64728581. The reversal of 64728531 is 13582746.

64728531 is a `hidden beast` number, since 647 + 2 + 8 + 5 + 3 + 1 = 666.

It is not a de Polignac number, because 64728531 - 2³ = 64728523 is a prime.

It is a super-2 number, since 2×64728531² = 8379565450835922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (64728511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36751 + ... + 38471.

It is an arithmetic number, because the mean of its divisors is an integer number (3444000).

Almost surely, 2^64728531 is an apocalyptic number.

64728531 is a deficient number, since it is larger than the sum of its proper divisors (45479469).

64728531 is a wasteful number, since it uses less digits than its factorization.

64728531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936 (or 1930 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 64728531 is about 8045.4043403672. The cubic root of 64728531 is about 401.5120499768.

The spelling of 64728531 in words is "sixty-four million, seven hundred twenty-eight thousand, five hundred thirty-one".