21251364116 has 24 divisors (see below), whose sum is σ = 37693545960. Its totient is φ = 10482481152.

The previous prime is 21251364109. The next prime is 21251364133. The reversal of 21251364116 is 61146315212.

It can be written as a sum of positive squares in 4 ways, for example, as 901200400 + 20350163716 = 30020^2 + 142654^2 .

It is a super-2 number, since 2×21251364116² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33950 + ... + 208938.

It is an arithmetic number, because the mean of its divisors is an integer number (1570564415).

Almost surely, 2^21251364116 is an apocalyptic number.

It is an amenable number.

21251364116 is a deficient number, since it is larger than the sum of its proper divisors (16442181844).

21251364116 is a wasteful number, since it uses less digits than its factorization.

21251364116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175403 (or 175401 counting only the distinct ones).

The product of its digits is 8640, while the sum is 32.

Adding to 21251364116 its reverse (61146315212), we get a palindrome (82397679328).

The spelling of 21251364116 in words is "twenty-one billion, two hundred fifty-one million, three hundred sixty-four thousand, one hundred sixteen".