21663410261640 has 512 divisors, whose sum is σ = 80482023014400. Its totient is φ = 4557516226560.

The previous prime is 21663410261609. The next prime is 21663410261651. The reversal of 21663410261640 is 4616201436612.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 21663410261592 and 21663410261601.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 57637441 + ... + 58012079.

It is an arithmetic number, because the mean of its divisors is an integer number (157191451200).

Almost surely, 2^{21663410261640} is an apocalyptic number.

21663410261640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21663410261640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40241011507200).

21663410261640 is an abundant number, since it is smaller than the sum of its proper divisors (58818612752760).

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

21663410261640 is a wasteful number, since it uses less digits than its factorization.

21663410261640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374797 (or 374793 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The spelling of 21663410261640 in words is "twenty-one trillion, six hundred sixty-three billion, four hundred ten million, two hundred sixty-one thousand, six hundred forty".