20997783812 has 12 divisors (see below), whose sum is σ = 36747686220. Its totient is φ = 10498444896.

The previous prime is 20997783811. The next prime is 20997783817. The reversal of 20997783812 is 21838779902.

It can be written as a sum of positive squares in 2 ways, for example, as 15924925636 + 5072858176 = 126194^2 + 71224^2 .

It is not an unprimeable number, because it can be changed into a prime (20997783811) 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, 8258 + ... + 205094.

It is an arithmetic number, because the mean of its divisors is an integer number (3062307185).

Almost surely, 2^20997783812 is an apocalyptic number.

It is an amenable number.

20997783812 is a deficient number, since it is larger than the sum of its proper divisors (15749902408).

20997783812 is a wasteful number, since it uses less digits than its factorization.

20997783812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223510 (or 223508 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 56.

The spelling of 20997783812 in words is "twenty billion, nine hundred ninety-seven million, seven hundred eighty-three thousand, eight hundred twelve".