21147812631 has 18 divisors (see below), whose sum is σ = 33576280920. Its totient is φ = 12816855480.

The previous prime is 21147812617. The next prime is 21147812657. The reversal of 21147812631 is 13621874112.

21147812631 is a `hidden beast` number, since 2 + 1 + 1 + 4 + 7 + 8 + 12 + 631 = 666.

It is not a de Polignac number, because 21147812631 - 2¹⁷ = 21147681559 is a prime.

It is a super-2 number, since 2×21147812631² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21147812681) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 9708651 + ... + 9710828.

It is an arithmetic number, because the mean of its divisors is an integer number (1865348940).

Almost surely, 2^21147812631 is an apocalyptic number.

21147812631 is a deficient number, since it is larger than the sum of its proper divisors (12428468289).

21147812631 is a wasteful number, since it uses less digits than its factorization.

21147812631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19419507 (or 19419493 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The spelling of 21147812631 in words is "twenty-one billion, one hundred forty-seven million, eight hundred twelve thousand, six hundred thirty-one".