20643761279 has 4 divisors (see below), whose sum is σ = 20767376784. Its totient is φ = 20520145776.

The previous prime is 20643761221. The next prime is 20643761287. The reversal of 20643761279 is 97216734602.

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 20643761279 - 2⁸ = 20643761023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643761209) 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, 61807502 + ... + 61807835.

It is an arithmetic number, because the mean of its divisors is an integer number (5191844196).

Almost surely, 2^20643761279 is an apocalyptic number.

20643761279 is a deficient number, since it is larger than the sum of its proper divisors (123615505).

20643761279 is a wasteful number, since it uses less digits than its factorization.

20643761279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123615504.

The product of its (nonzero) digits is 762048, while the sum is 47.

The spelling of 20643761279 in words is "twenty billion, six hundred forty-three million, seven hundred sixty-one thousand, two hundred seventy-nine".