20508197994 has 24 divisors (see below), whose sum is σ = 45867798912. Its totient is φ = 6615547560.

The previous prime is 20508197993. The next prime is 20508198001. The reversal of 20508197994 is 49979180502.

It is a super-2 number, since 2×20508197994² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20508197994.

It is not an unprimeable number, because it can be changed into a prime (20508197993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18375964 + ... + 18377079.

It is an arithmetic number, because the mean of its divisors is an integer number (1911158288).

Almost surely, 2^20508197994 is an apocalyptic number.

20508197994 is an abundant number, since it is smaller than the sum of its proper divisors (25359600918).

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

20508197994 is a wasteful number, since it uses less digits than its factorization.

20508197994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36753082 (or 36753079 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 54.

The spelling of 20508197994 in words is "twenty billion, five hundred eight million, one hundred ninety-seven thousand, nine hundred ninety-four".