21670357828212 has 72 divisors (see below), whose sum is σ = 55876521636936. Its totient is φ = 7078890783744.

The previous prime is 21670357828211. The next prime is 21670357828271. The reversal of 21670357828212 is 21282875307612.

21670357828212 is a `hidden beast` number, since 2 + 1 + 6 + 7 + 0 + 357 + 8 + 282 + 1 + 2 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 12173581552356 + 9496776275856 = 3489066^2 + 3081684^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21670357828211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4991233 + ... + 8261544.

It is an arithmetic number, because the mean of its divisors is an integer number (776062800513).

Almost surely, 2^{21670357828212} is an apocalyptic number.

It is an amenable number.

21670357828212 is an abundant number, since it is smaller than the sum of its proper divisors (34206163808724).

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

21670357828212 is a wasteful number, since it uses less digits than its factorization.

21670357828212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13253697 (or 13253692 counting only the distinct ones).

The product of its (nonzero) digits is 4515840, while the sum is 54.

The spelling of 21670357828212 in words is "twenty-one trillion, six hundred seventy billion, three hundred fifty-seven million, eight hundred twenty-eight thousand, two hundred twelve".