21149990400 has 960 divisors, whose sum is σ = 91187306496. Its totient is φ = 4190208000.

The previous prime is 21149990399. The next prime is 21149990401. The reversal of 21149990400 is 409994112.

It is an interprime number because it is at equal distance from previous prime (21149990399) and next prime (21149990401).

It is a tau number, because it is divible by the number of its divisors (960).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21149990401) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 68006245 + ... + 68006555.

Almost surely, 2^21149990400 is an apocalyptic number.

21149990400 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 21149990400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45593653248).

21149990400 is an abundant number, since it is smaller than the sum of its proper divisors (70037316096).

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

21149990400 is a wasteful number, since it uses less digits than its factorization.

21149990400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383 (or 362 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 39.

The spelling of 21149990400 in words is "twenty-one billion, one hundred forty-nine million, nine hundred ninety thousand, four hundred".