20719891879 has 4 divisors (see below), whose sum is σ = 21388275520. Its totient is φ = 20051508240.

The previous prime is 20719891867. The next prime is 20719891889. The reversal of 20719891879 is 97819891702.

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 20719891879 - 2⁵ = 20719891847 is a prime.

It is a super-3 number, since 3×20719891879³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20719891889) 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, 334191774 + ... + 334191835.

It is an arithmetic number, because the mean of its divisors is an integer number (5347068880).

Almost surely, 2^20719891879 is an apocalyptic number.

20719891879 is a deficient number, since it is larger than the sum of its proper divisors (668383641).

20719891879 is an equidigital number, since it uses as much as digits as its factorization.

20719891879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 668383640.

The product of its (nonzero) digits is 4572288, while the sum is 61.

The spelling of 20719891879 in words is "twenty billion, seven hundred nineteen million, eight hundred ninety-one thousand, eight hundred seventy-nine".