21408503400 has 144 divisors (see below), whose sum is σ = 73840279500. Its totient is φ = 5554621440.

The previous prime is 21408503383. The next prime is 21408503401. The reversal of 21408503400 is 430580412.

It can be written as a sum of positive squares in 6 ways, for example, as 9887915844 + 11520587556 = 99438^2 + 107334^2 .

It is not an unprimeable number, because it can be changed into a prime (21408503401) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 94125 + ... + 227324.

Almost surely, 2^21408503400 is an apocalyptic number.

21408503400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21408503400 is an abundant number, since it is smaller than the sum of its proper divisors (52431776100).

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

21408503400 is a wasteful number, since it uses less digits than its factorization.

21408503400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321508 (or 321496 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The spelling of 21408503400 in words is "twenty-one billion, four hundred eight million, five hundred three thousand, four hundred".