20863866564 has 18 divisors (see below), whose sum is σ = 52739218350. Its totient is φ = 6954622176.

The previous prime is 20863866553. The next prime is 20863866571. The reversal of 20863866564 is 46566836802.

It is a happy number.

20863866564 is a `hidden beast` number, since 208 + 6 + 386 + 6 + 56 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12850036164 + 8013830400 = 113358^2 + 89520^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a self number, because there is not a number n which added to its sum of digits gives 20863866564.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 289775889 + ... + 289775960.

It is an arithmetic number, because the mean of its divisors is an integer number (2929956575).

Almost surely, 2^20863866564 is an apocalyptic number.

It is an amenable number.

20863866564 is an abundant number, since it is smaller than the sum of its proper divisors (31875351786).

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

20863866564 is a wasteful number, since it uses less digits than its factorization.

20863866564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579551859 (or 579551854 counting only the distinct ones).

The product of its (nonzero) digits is 9953280, while the sum is 54.

The spelling of 20863866564 in words is "twenty billion, eight hundred sixty-three million, eight hundred sixty-six thousand, five hundred sixty-four".