64861257 has 4 divisors (see below), whose sum is σ = 86481680. Its totient is φ = 43240836.

The previous prime is 64861249. The next prime is 64861261. The reversal of 64861257 is 75216846.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 64861257 - 2³ = 64861249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64861217) 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, 10810207 + ... + 10810212.

It is an arithmetic number, because the mean of its divisors is an integer number (21620420).

Almost surely, 2^64861257 is an apocalyptic number.

It is an amenable number.

64861257 is a deficient number, since it is larger than the sum of its proper divisors (21620423).

64861257 is a wasteful number, since it uses less digits than its factorization.

64861257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21620422.

The product of its digits is 80640, while the sum is 39.

The square root of 64861257 is about 8053.6486762212. The cubic root of 64861257 is about 401.7862964049.

The spelling of 64861257 in words is "sixty-four million, eight hundred sixty-one thousand, two hundred fifty-seven".