21131132400 has 720 divisors, whose sum is σ = 86851336000. Its totient is φ = 4755179520.

The previous prime is 21131132377. The next prime is 21131132411. The reversal of 21131132400 is 423113112.

21131132400 is a `hidden beast` number, since 2 + 1 + 131 + 132 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 134593122 + ... + 134593278.

Almost surely, 2^21131132400 is an apocalyptic number.

21131132400 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 21131132400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43425668000).

21131132400 is an abundant number, since it is smaller than the sum of its proper divisors (65720203600).

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

21131132400 is a wasteful number, since it uses less digits than its factorization.

21131132400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21131132400 its reverse (423113112), we get a palindrome (21554245512).

The spelling of 21131132400 in words is "twenty-one billion, one hundred thirty-one million, one hundred thirty-two thousand, four hundred".