20909801983 has 4 divisors (see below), whose sum is σ = 23896916560. Its totient is φ = 17922687408.

The previous prime is 20909801921. The next prime is 20909801987. The reversal of 20909801983 is 38910890902.

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 20909801983 - 2¹³ = 20909793791 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 (20909801987) 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, 1493557278 + ... + 1493557291.

It is an arithmetic number, because the mean of its divisors is an integer number (5974229140).

Almost surely, 2^20909801983 is an apocalyptic number.

20909801983 is a deficient number, since it is larger than the sum of its proper divisors (2987114577).

20909801983 is an equidigital number, since it uses as much as digits as its factorization.

20909801983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2987114576.

The product of its (nonzero) digits is 279936, while the sum is 49.

The spelling of 20909801983 in words is "twenty billion, nine hundred nine million, eight hundred one thousand, nine hundred eighty-three".