21660540503424 has 128 divisors (see below), whose sum is σ = 57611824905600. Its totient is φ = 7210647822336.

The previous prime is 21660540503423. The next prime is 21660540503453. The reversal of 21660540503424 is 42430504506612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660540503423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 941628307 + ... + 941651309.

It is an arithmetic number, because the mean of its divisors is an integer number (450092382075).

Almost surely, 2^{21660540503424} is an apocalyptic number.

21660540503424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21660540503424 is an abundant number, since it is smaller than the sum of its proper divisors (35951284402176).

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

21660540503424 is a wasteful number, since it uses less digits than its factorization.

21660540503424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26152 (or 26140 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 42.

The spelling of 21660540503424 in words is "twenty-one trillion, six hundred sixty billion, five hundred forty million, five hundred three thousand, four hundred twenty-four".