65631531621 has 8 divisors (see below), whose sum is σ = 88707458560. Its totient is φ = 43154979552.

The previous prime is 65631531613. The next prime is 65631531659. The reversal of 65631531621 is 12613513656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65631531621 - 2³ = 65631531613 is a prime.

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 65631531621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65631531421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 149843461 + ... + 149843898.

It is an arithmetic number, because the mean of its divisors is an integer number (11088432320).

Almost surely, 2^65631531621 is an apocalyptic number.

It is an amenable number.

65631531621 is a deficient number, since it is larger than the sum of its proper divisors (23075926939).

65631531621 is a wasteful number, since it uses less digits than its factorization.

65631531621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299687435.

The product of its digits is 97200, while the sum is 39.

The spelling of 65631531621 in words is "sixty-five billion, six hundred thirty-one million, five hundred thirty-one thousand, six hundred twenty-one".