21125213112 has 16 divisors (see below), whose sum is σ = 52813032840. Its totient is φ = 7041737696.

The previous prime is 21125213101. The next prime is 21125213117. The reversal of 21125213112 is 21131252112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125213117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 440108583 + ... + 440108630.

Almost surely, 2^21125213112 is an apocalyptic number.

It is an amenable number.

21125213112 is an abundant number, since it is smaller than the sum of its proper divisors (31687819728).

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

21125213112 is a wasteful number, since it uses less digits than its factorization.

21125213112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880217222 (or 880217218 counting only the distinct ones).

The product of its digits is 240, while the sum is 21.

Adding to 21125213112 its reverse (21131252112), we get a palindrome (42256465224).

The spelling of 21125213112 in words is "twenty-one billion, one hundred twenty-five million, two hundred thirteen thousand, one hundred twelve".