20864491866 has 32 divisors (see below), whose sum is σ = 46379085120. Its totient is φ = 6952798512.

The previous prime is 20864491829. The next prime is 20864491957. The reversal of 20864491866 is 66819446802.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136101 + ... + 245463.

It is an arithmetic number, because the mean of its divisors is an integer number (1449346410).

Almost surely, 2^20864491866 is an apocalyptic number.

20864491866 is an abundant number, since it is smaller than the sum of its proper divisors (25514593254).

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

20864491866 is a wasteful number, since it uses less digits than its factorization.

20864491866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112907 (or 112901 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The spelling of 20864491866 in words is "twenty billion, eight hundred sixty-four million, four hundred ninety-one thousand, eight hundred sixty-six".