21255012312 has 32 divisors (see below), whose sum is σ = 53143500480. Its totient is φ = 7084208160.

The previous prime is 21255012299. The next prime is 21255012319. The reversal of 21255012312 is 21321055212.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255012319) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192387 + ... + 281997.

It is an arithmetic number, because the mean of its divisors is an integer number (1660734390).

Almost surely, 2^21255012312 is an apocalyptic number.

It is an amenable number.

21255012312 is an abundant number, since it is smaller than the sum of its proper divisors (31888488168).

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

21255012312 is a wasteful number, since it uses less digits than its factorization.

21255012312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99503 (or 99499 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21255012312 its reverse (21321055212), we get a palindrome (42576067524).

The spelling of 21255012312 in words is "twenty-one billion, two hundred fifty-five million, twelve thousand, three hundred twelve".