21825168164 has 12 divisors (see below), whose sum is σ = 38226392988. Its totient is φ = 10903341600.

The previous prime is 21825168163. The next prime is 21825168199. The reversal of 21825168164 is 46186152812.

It can be written as a sum of positive squares in 2 ways, for example, as 18917801764 + 2907366400 = 137542^2 + 53920^2 .

It is not an unprimeable number, because it can be changed into a prime (21825168163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2305307 + ... + 2314754.

It is an arithmetic number, because the mean of its divisors is an integer number (3185532749).

Almost surely, 2^21825168164 is an apocalyptic number.

It is an amenable number.

21825168164 is a deficient number, since it is larger than the sum of its proper divisors (16401224824).

21825168164 is a wasteful number, since it uses less digits than its factorization.

21825168164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4621246 (or 4621244 counting only the distinct ones).

The product of its digits is 184320, while the sum is 44.

The spelling of 21825168164 in words is "twenty-one billion, eight hundred twenty-five million, one hundred sixty-eight thousand, one hundred sixty-four".