21131540544 has 56 divisors (see below), whose sum is σ = 55923533568. Its totient is φ = 7042209280.

The previous prime is 21131540533. The next prime is 21131540561. The reversal of 21131540544 is 44504513112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1040374 + ... + 1060490.

It is an arithmetic number, because the mean of its divisors is an integer number (998634528).

Almost surely, 2^21131540544 is an apocalyptic number.

21131540544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21131540544 is an abundant number, since it is smaller than the sum of its proper divisors (34791993024).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21131540544 is a wasteful number, since it uses less digits than its factorization.

21131540544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25603 (or 25593 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The spelling of 21131540544 in words is "twenty-one billion, one hundred thirty-one million, five hundred forty thousand, five hundred forty-four".