20201209979 has 4 divisors (see below), whose sum is σ = 20206931376. Its totient is φ = 20195488584.

The previous prime is 20201209969. The next prime is 20201209981. The reversal of 20201209979 is 97990210202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97990210202 = 2 ⋅48995105101.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20201209979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20201209969) 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, 2855399 + ... + 2862464.

It is an arithmetic number, because the mean of its divisors is an integer number (5051732844).

Almost surely, 2^20201209979 is an apocalyptic number.

20201209979 is a deficient number, since it is larger than the sum of its proper divisors (5721397).

20201209979 is an equidigital number, since it uses as much as digits as its factorization.

20201209979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5721396.

The product of its (nonzero) digits is 40824, while the sum is 41.

The spelling of 20201209979 in words is "twenty billion, two hundred one million, two hundred nine thousand, nine hundred seventy-nine".