21663523553240 has 32 divisors (see below), whose sum is σ = 50423718618000. Its totient is φ = 8366602199424.

The previous prime is 21663523553167. The next prime is 21663523553257. The reversal of 21663523553240 is 4235532536612.

It is a happy number.

It is a super-2 number, since 2×21663523553240² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

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, 9337724510 + ... + 9337726829.

Almost surely, 2^{21663523553240} is an apocalyptic number.

21663523553240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21663523553240 is an abundant number, since it is smaller than the sum of its proper divisors (28760195064760).

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

21663523553240 is a wasteful number, since it uses less digits than its factorization.

21663523553240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18675451379 (or 18675451375 counting only the distinct ones).

The product of its (nonzero) digits is 3888000, while the sum is 47.

The spelling of 21663523553240 in words is "twenty-one trillion, six hundred sixty-three billion, five hundred twenty-three million, five hundred fifty-three thousand, two hundred forty".