64691531 has 8 divisors (see below), whose sum is σ = 65585520. Its totient is φ = 63802368.

The previous prime is 64691527. The next prime is 64691551. The reversal of 64691531 is 13519646.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 64691531 - 2² = 64691527 is a prime.

It is a super-2 number, since 2×64691531² = 8369988366247922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64691491 and 64691500.

It is not an unprimeable number, because it can be changed into a prime (64691521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31700 + ... + 33678.

It is an arithmetic number, because the mean of its divisors is an integer number (8198190).

Almost surely, 2^64691531 is an apocalyptic number.

64691531 is a deficient number, since it is larger than the sum of its proper divisors (893989).

64691531 is a wasteful number, since it uses less digits than its factorization.

64691531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413.

The product of its digits is 19440, while the sum is 35.

The square root of 64691531 is about 8043.1045622943. The cubic root of 64691531 is about 401.4355315432.

It can be divided in two parts, 6469 and 1531, that added together give a cube (8000 = 20³).

The spelling of 64691531 in words is "sixty-four million, six hundred ninety-one thousand, five hundred thirty-one".