65431921 has 3 divisors (see below), whose sum is σ = 65440011. Its totient is φ = 65423832.

The previous prime is 65431913. The next prime is 65431931. The reversal of 65431921 is 12913456.

The square root of 65431921 is 8089.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 790321 + 64641600 = 889^2 + 8040^2 .

It is not a de Polignac number, because 65431921 - 2³ = 65431913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65431901) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4045 + ... + 12133.

It is an arithmetic number, because the mean of its divisors is an integer number (21813337).

Almost surely, 2^65431921 is an apocalyptic number.

65431921 is the 8089-th square number.

65431921 is the 4045-th centered octagonal number.

It is an amenable number.

65431921 is a deficient number, since it is larger than the sum of its proper divisors (8090).

65431921 is an frugal number, since it uses more digits than its factorization.

65431921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16178 (or 8089 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The cubic root of 65431921 is about 402.9611929949.

It can be divided in two parts, 6543 and 1921, that added together give a square (8464 = 92²).

The spelling of 65431921 in words is "sixty-five million, four hundred thirty-one thousand, nine hundred twenty-one".