21518647717120 has 72 divisors (see below), whose sum is σ = 52742581014816. Its totient is φ = 8407285598208.

The previous prime is 21518647717087. The next prime is 21518647717121. The reversal of 21518647717120 is 2171774681512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21518647717121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195426862 + ... + 195536941.

It is an arithmetic number, because the mean of its divisors is an integer number (732535847428).

Almost surely, 2^{21518647717120} is an apocalyptic number.

21518647717120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21518647717120 is an abundant number, since it is smaller than the sum of its proper divisors (31223933297696).

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

21518647717120 is an equidigital number, since it uses as much as digits as its factorization.

21518647717120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390963867 (or 390963853 counting only the distinct ones).

The product of its (nonzero) digits is 1317120, while the sum is 52.

The spelling of 21518647717120 in words is "twenty-one trillion, five hundred eighteen billion, six hundred forty-seven million, seven hundred seventeen thousand, one hundred twenty".