65921731 has 4 divisors (see below), whose sum is σ = 66069000. Its totient is φ = 65774464.

The previous prime is 65921729. The next prime is 65921759. The reversal of 65921731 is 13712956.

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 65921731 - 2¹ = 65921729 is a prime.

It is a super-2 number, since 2×65921731² = 8691349236072722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65921711) 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, 72961 + ... + 73858.

It is an arithmetic number, because the mean of its divisors is an integer number (16517250).

Almost surely, 2^65921731 is an apocalyptic number.

65921731 is a deficient number, since it is larger than the sum of its proper divisors (147269).

65921731 is a wasteful number, since it uses less digits than its factorization.

65921731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147268.

The product of its digits is 11340, while the sum is 34.

The square root of 65921731 is about 8119.2198516853. The cubic root of 65921731 is about 403.9641894704.

The spelling of 65921731 in words is "sixty-five million, nine hundred twenty-one thousand, seven hundred thirty-one".