64691139 has 4 divisors (see below), whose sum is σ = 86254856. Its totient is φ = 43127424.

The previous prime is 64691093. The next prime is 64691149. The reversal of 64691139 is 93119646.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 64691139 - 2²¹ = 62593987 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 64691097 and 64691106.

It is not an unprimeable number, because it can be changed into a prime (64691149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10781854 + ... + 10781859.

It is an arithmetic number, because the mean of its divisors is an integer number (21563714).

Almost surely, 2^64691139 is an apocalyptic number.

64691139 is a deficient number, since it is larger than the sum of its proper divisors (21563717).

64691139 is a wasteful number, since it uses less digits than its factorization.

64691139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21563716.

The product of its digits is 34992, while the sum is 39.

The square root of 64691139 is about 8043.0801935577. The cubic root of 64691139 is about 401.4347207053.

The spelling of 64691139 in words is "sixty-four million, six hundred ninety-one thousand, one hundred thirty-nine".