20512663651 has 4 divisors (see below), whose sum is σ = 20514895992. Its totient is φ = 20510431312.

The previous prime is 20512663631. The next prime is 20512663657. The reversal of 20512663651 is 15636621502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20512663651 - 2⁹ = 20512663139 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20512663651.

It is not an unprimeable number, because it can be changed into a prime (20512663657) 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, 1102330 + ... + 1120783.

It is an arithmetic number, because the mean of its divisors is an integer number (5128723998).

Almost surely, 2^20512663651 is an apocalyptic number.

20512663651 is a deficient number, since it is larger than the sum of its proper divisors (2232341).

20512663651 is an equidigital number, since it uses as much as digits as its factorization.

20512663651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2232340.

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 20512663651 in words is "twenty billion, five hundred twelve million, six hundred sixty-three thousand, six hundred fifty-one".