21674581812 has 72 divisors (see below), whose sum is σ = 59026973096. Its totient is φ = 6666395904.

The previous prime is 21674581811. The next prime is 21674581847. The reversal of 21674581812 is 21818547612.

21674581812 is a `hidden beast` number, since 2 + 1 + 67 + 4 + 581 + 8 + 1 + 2 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 14470646436 + 7203935376 = 120294^2 + 84876^2 .

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21674581811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1357218 + ... + 1373094.

Almost surely, 2^21674581812 is an apocalyptic number.

It is an amenable number.

21674581812 is an abundant number, since it is smaller than the sum of its proper divisors (37352391284).

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

21674581812 is a wasteful number, since it uses less digits than its factorization.

21674581812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18817 (or 18812 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The spelling of 21674581812 in words is "twenty-one billion, six hundred seventy-four million, five hundred eighty-one thousand, eight hundred twelve".