20896891639 has 4 divisors (see below), whose sum is σ = 22504344856. Its totient is φ = 19289438424.

The previous prime is 20896891621. The next prime is 20896891651. The reversal of 20896891639 is 93619869802.

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 20896891639 - 2¹⁹ = 20896367351 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 (20896891139) 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, 803726589 + ... + 803726614.

It is an arithmetic number, because the mean of its divisors is an integer number (5626086214).

Almost surely, 2^20896891639 is an apocalyptic number.

20896891639 is a deficient number, since it is larger than the sum of its proper divisors (1607453217).

20896891639 is a wasteful number, since it uses less digits than its factorization.

20896891639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1607453216.

The product of its (nonzero) digits is 10077696, while the sum is 61.

The spelling of 20896891639 in words is "twenty billion, eight hundred ninety-six million, eight hundred ninety-one thousand, six hundred thirty-nine".