64713781 has 16 divisors (see below), whose sum is σ = 75022848. Its totient is φ = 55168000.

The previous prime is 64713763. The next prime is 64713787. The reversal of 64713781 is 18731746.

It is a cyclic number.

It is not a de Polignac number, because 64713781 - 2⁵ = 64713749 is a prime.

It is a super-2 number, since 2×64713781² = 8375746902631922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64713781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64713787) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74556 + ... + 75418.

It is an arithmetic number, because the mean of its divisors is an integer number (4688928).

Almost surely, 2^64713781 is an apocalyptic number.

It is an amenable number.

64713781 is a deficient number, since it is larger than the sum of its proper divisors (10309067).

64713781 is a wasteful number, since it uses less digits than its factorization.

64713781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1292.

The product of its digits is 28224, while the sum is 37.

The square root of 64713781 is about 8044.4876157528. The cubic root of 64713781 is about 401.4815495027.

The spelling of 64713781 in words is "sixty-four million, seven hundred thirteen thousand, seven hundred eighty-one".