21670356852 has 18 divisors (see below), whose sum is σ = 54777846578. Its totient is φ = 7223452272.

The previous prime is 21670356781. The next prime is 21670356857. The reversal of 21670356852 is 25865307612.

21670356852 is a `hidden beast` number, since 2 + 16 + 70 + 3 + 568 + 5 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21276889956 + 393466896 = 145866^2 + 19836^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21670356798 and 21670356807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21670356857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 300977143 + ... + 300977214.

Almost surely, 2^21670356852 is an apocalyptic number.

It is an amenable number.

21670356852 is an abundant number, since it is smaller than the sum of its proper divisors (33107489726).

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

21670356852 is a wasteful number, since it uses less digits than its factorization.

21670356852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601954367 (or 601954362 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 45.

The spelling of 21670356852 in words is "twenty-one billion, six hundred seventy million, three hundred fifty-six thousand, eight hundred fifty-two".