20821170492 has 18 divisors (see below), whose sum is σ = 52631292168. Its totient is φ = 6940390152.

The previous prime is 20821170479. The next prime is 20821170499. The reversal of 20821170492 is 29407112802.

20821170492 is a `hidden beast` number, since 20 + 82 + 1 + 1 + 70 + 492 = 666.

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

It is a super-2 number, since 2×20821170492² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 578365847 = 20821170492 / (2 + 0 + 8 + 2 + 1 + 1 + 7 + 0 + 4 + 9 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20821170499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 289182888 + ... + 289182959.

It is an arithmetic number, because the mean of its divisors is an integer number (2923960676).

Almost surely, 2^20821170492 is an apocalyptic number.

It is an amenable number.

20821170492 is an abundant number, since it is smaller than the sum of its proper divisors (31810121676).

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

20821170492 is a wasteful number, since it uses less digits than its factorization.

20821170492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578365857 (or 578365852 counting only the distinct ones).

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

The spelling of 20821170492 in words is "twenty billion, eight hundred twenty-one million, one hundred seventy thousand, four hundred ninety-two".