64139947 has 4 divisors (see below), whose sum is σ = 64220040. Its totient is φ = 64059856.

The previous prime is 64139927. The next prime is 64139951. The reversal of 64139947 is 74993146.

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

It is a de Polignac number, because none of the positive numbers 2^k-64139947 is a prime.

It is a super-2 number, since 2×64139947² = 8227865602325618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64139927) 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, 38833 + ... + 40450.

It is an arithmetic number, because the mean of its divisors is an integer number (16055010).

Almost surely, 2^64139947 is an apocalyptic number.

64139947 is a deficient number, since it is larger than the sum of its proper divisors (80093).

64139947 is an equidigital number, since it uses as much as digits as its factorization.

64139947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80092.

The product of its digits is 163296, while the sum is 43.

The square root of 64139947 is about 8008.7419111868. The cubic root of 64139947 is about 400.2913439952.

The spelling of 64139947 in words is "sixty-four million, one hundred thirty-nine thousand, nine hundred forty-seven".