20401109979 has 16 divisors (see below), whose sum is σ = 28151366400. Its totient is φ = 13126193696.

The previous prime is 20401109977. The next prime is 20401109999. The reversal of 20401109979 is 97990110402.

It is a cyclic number.

It is not a de Polignac number, because 20401109979 - 2¹ = 20401109977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20401109979.

It is not an unprimeable number, because it can be changed into a prime (20401109977) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 162412 + ... + 259190.

It is an arithmetic number, because the mean of its divisors is an integer number (1759460400).

Almost surely, 2^20401109979 is an apocalyptic number.

20401109979 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

20401109979 is a deficient number, since it is larger than the sum of its proper divisors (7750256421).

20401109979 is a wasteful number, since it uses less digits than its factorization.

20401109979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99234.

The product of its (nonzero) digits is 40824, while the sum is 42.

The spelling of 20401109979 in words is "twenty billion, four hundred one million, one hundred nine thousand, nine hundred seventy-nine".