21405902280 has 128 divisors (see below), whose sum is σ = 73422720000. Its totient is φ = 4890707712.

The previous prime is 21405902261. The next prime is 21405902281. The reversal of 21405902280 is 8220950412.

It is not an unprimeable number, because it can be changed into a prime (21405902281) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2935519 + ... + 2942801.

It is an arithmetic number, because the mean of its divisors is an integer number (573615000).

Almost surely, 2^21405902280 is an apocalyptic number.

21405902280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21405902280 is an abundant number, since it is smaller than the sum of its proper divisors (52016817720).

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

21405902280 is a wasteful number, since it uses less digits than its factorization.

21405902280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10803 (or 10799 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The spelling of 21405902280 in words is "twenty-one billion, four hundred five million, nine hundred two thousand, two hundred eighty".