21131451200 has 84 divisors (see below), whose sum is σ = 52287769440. Its totient is φ = 8405245440.

The previous prime is 21131451191. The next prime is 21131451247. The reversal of 21131451200 is 215413112.

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 249509 + ... + 323291.

Almost surely, 2^21131451200 is an apocalyptic number.

21131451200 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 21131451200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26143884720).

21131451200 is an abundant number, since it is smaller than the sum of its proper divisors (31156318240).

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

21131451200 is a wasteful number, since it uses less digits than its factorization.

21131451200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73984 (or 73969 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21131451200 its reverse (215413112), we get a palindrome (21346864312).

The spelling of 21131451200 in words is "twenty-one billion, one hundred thirty-one million, four hundred fifty-one thousand, two hundred".