20994886836 has 144 divisors (see below), whose sum is σ = 69648284160. Its totient is φ = 5166192960.

The previous prime is 20994886823. The next prime is 20994886837. The reversal of 20994886836 is 63868849902.

20994886836 is a `hidden beast` number, since 2 + 0 + 99 + 488 + 68 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20994886837) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 146646 + ... + 251981.

It is an arithmetic number, because the mean of its divisors is an integer number (483668640).

Almost surely, 2^20994886836 is an apocalyptic number.

It is an amenable number.

20994886836 is an abundant number, since it is smaller than the sum of its proper divisors (48653397324).

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

20994886836 is a wasteful number, since it uses less digits than its factorization.

20994886836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398674 (or 398669 counting only the distinct ones).

The product of its (nonzero) digits is 35831808, while the sum is 63.

The spelling of 20994886836 in words is "twenty billion, nine hundred ninety-four million, eight hundred eighty-six thousand, eight hundred thirty-six".