21001510400 has 120 divisors (see below), whose sum is σ = 56035856184. Its totient is φ = 7754342400.

The previous prime is 21001510399. The next prime is 21001510421. The reversal of 21001510400 is 401510012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 103295 + ... + 229505.

Almost surely, 2^21001510400 is an apocalyptic number.

21001510400 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 21001510400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28017928092).

21001510400 is an abundant number, since it is smaller than the sum of its proper divisors (35034345784).

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

21001510400 is a wasteful number, since it uses less digits than its factorization.

21001510400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126252 (or 126231 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The spelling of 21001510400 in words is "twenty-one billion, one million, five hundred ten thousand, four hundred".