20980926391 has 4 divisors (see below), whose sum is σ = 20987828784. Its totient is φ = 20974024000.

The previous prime is 20980926371. The next prime is 20980926437. The reversal of 20980926391 is 19362908902.

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 20980926391 - 2²³ = 20972537783 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20980926361) 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, 3446635 + ... + 3452716.

It is an arithmetic number, because the mean of its divisors is an integer number (5246957196).

Almost surely, 2^20980926391 is an apocalyptic number.

20980926391 is a deficient number, since it is larger than the sum of its proper divisors (6902393).

20980926391 is an equidigital number, since it uses as much as digits as its factorization.

20980926391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6902392.

The product of its (nonzero) digits is 419904, while the sum is 49.

The spelling of 20980926391 in words is "twenty billion, nine hundred eighty million, nine hundred twenty-six thousand, three hundred ninety-one".