21123632537280 has 3584 divisors, whose sum is σ = 99766453248000. Its totient is φ = 4132984061952.

The previous prime is 21123632537261. The next prime is 21123632537309. The reversal of 21123632537280 is 8273523632112.

It is a happy number.

21123632537280 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 3 + 6 + 32 + 537 + 2 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 511 ways as a sum of consecutive naturals, for example, 118009120231 + ... + 118009120409.

It is an arithmetic number, because the mean of its divisors is an integer number (27836622000).

Almost surely, 2^{21123632537280} is an apocalyptic number.

21123632537280 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 21123632537280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49883226624000).

21123632537280 is an abundant number, since it is smaller than the sum of its proper divisors (78642820710720).

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

21123632537280 is a wasteful number, since it uses less digits than its factorization.

21123632537280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The spelling of 21123632537280 in words is "twenty-one trillion, one hundred twenty-three billion, six hundred thirty-two million, five hundred thirty-seven thousand, two hundred eighty".