65778731 has 4 divisors (see below), whose sum is σ = 66705264. Its totient is φ = 64852200.

The previous prime is 65778697. The next prime is 65778737. The reversal of 65778731 is 13787756.

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

It is a cyclic number.

It is not a de Polignac number, because 65778731 - 2¹⁰ = 65777707 is a prime.

It is a super-2 number, since 2×65778731² = 8653682903940722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65778737) 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, 463160 + ... + 463301.

It is an arithmetic number, because the mean of its divisors is an integer number (16676316).

Almost surely, 2^65778731 is an apocalyptic number.

65778731 is a deficient number, since it is larger than the sum of its proper divisors (926533).

65778731 is an equidigital number, since it uses as much as digits as its factorization.

65778731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 926532.

The product of its digits is 246960, while the sum is 44.

The square root of 65778731 is about 8110.4088059727. The cubic root of 65778731 is about 403.6718796929.

The spelling of 65778731 in words is "sixty-five million, seven hundred seventy-eight thousand, seven hundred thirty-one".