21312070400 has 108 divisors (see below), whose sum is σ = 55853971992. Its totient is φ = 8023326720.

The previous prime is 21312070399. The next prime is 21312070441. The reversal of 21312070400 is 407021312.

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

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, 10859 + ... + 206741.

Almost surely, 2^21312070400 is an apocalyptic number.

21312070400 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 21312070400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27926985996).

21312070400 is an abundant number, since it is smaller than the sum of its proper divisors (34541901592).

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

21312070400 is a wasteful number, since it uses less digits than its factorization.

21312070400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195926 (or 195907 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

Adding to 21312070400 its reverse (407021312), we get a palindrome (21719091712).

The spelling of 21312070400 in words is "twenty-one billion, three hundred twelve million, seventy thousand, four hundred".