20001563977 has 4 divisors (see below), whose sum is σ = 20427129216. Its totient is φ = 19575998740.

The previous prime is 20001563963. The next prime is 20001564001. The reversal of 20001563977 is 77936510002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20001563977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20001563917) 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, 212782549 + ... + 212782642.

It is an arithmetic number, because the mean of its divisors is an integer number (5106782304).

Almost surely, 2^20001563977 is an apocalyptic number.

It is an amenable number.

20001563977 is a deficient number, since it is larger than the sum of its proper divisors (425565239).

20001563977 is an equidigital number, since it uses as much as digits as its factorization.

20001563977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425565238.

The product of its (nonzero) digits is 79380, while the sum is 40.

The spelling of 20001563977 in words is "twenty billion, one million, five hundred sixty-three thousand, nine hundred seventy-seven".