16721531631 has 24 divisors (see below), whose sum is σ = 28555656480. Its totient is φ = 9225671616.

The previous prime is 16721531611. The next prime is 16721531639. The reversal of 16721531631 is 13613512761.

16721531631 is a `hidden beast` number, since 1 + 6 + 7 + 2 + 15 + 3 + 1 + 631 = 666.

It is not a de Polignac number, because 16721531631 - 2²³ = 16713143023 is a prime.

It is a super-2 number, since 2×16721531631² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16721531639) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4574400 + ... + 4578053.

It is an arithmetic number, because the mean of its divisors is an integer number (1189819020).

Almost surely, 2^16721531631 is an apocalyptic number.

16721531631 is a deficient number, since it is larger than the sum of its proper divisors (11834124849).

16721531631 is a wasteful number, since it uses less digits than its factorization.

16721531631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9152495 (or 9152492 counting only the distinct ones).

The product of its digits is 22680, while the sum is 36.

The spelling of 16721531631 in words is "sixteen billion, seven hundred twenty-one million, five hundred thirty-one thousand, six hundred thirty-one".