20821912804 has 81 divisors (see below), whose sum is σ = 46640957769. Its totient is φ = 8103775680.

The previous prime is 20821912801. The next prime is 20821912819. The reversal of 20821912804 is 40821912802.

It is a happy number.

The square root of 20821912804 is 144298.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1096272100 + 19725640704 = 33110^2 + 140448^2 .

It is not an unprimeable number, because it can be changed into a prime (20821912801) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 22221424 + ... + 22222360.

Almost surely, 2^20821912804 is an apocalyptic number.

20821912804 is the 144298-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20821912804

20821912804 is an abundant number, since it is smaller than the sum of its proper divisors (25819044965).

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

20821912804 is an equidigital number, since it uses as much as digits as its factorization.

20821912804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1914 (or 957 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 37.

The spelling of 20821912804 in words is "twenty billion, eight hundred twenty-one million, nine hundred twelve thousand, eight hundred four".