21042521280 has 896 divisors, whose sum is σ = 87548313600. Its totient is φ = 4702924800.

The previous prime is 21042521251. The next prime is 21042521303. The reversal of 21042521280 is 8212524012.

21042521280 is a `hidden beast` number, since 21 + 0 + 42 + 521 + 2 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 77647545 + ... + 77647815.

Almost surely, 2^21042521280 is an apocalyptic number.

21042521280 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 21042521280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43774156800).

21042521280 is an abundant number, since it is smaller than the sum of its proper divisors (66505792320).

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

21042521280 is a wasteful number, since it uses less digits than its factorization.

21042521280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The spelling of 21042521280 in words is "twenty-one billion, forty-two million, five hundred twenty-one thousand, two hundred eighty".