20808079421 has 4 divisors (see below), whose sum is σ = 20810486172. Its totient is φ = 20805672672.

The previous prime is 20808079417. The next prime is 20808079429. The reversal of 20808079421 is 12497080802.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9260212900 + 11547866521 = 96230^2 + 107461^2 .

It is a cyclic number.

It is not a de Polignac number, because 20808079421 - 2² = 20808079417 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 (20808079429) 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, 1190360 + ... + 1207713.

It is an arithmetic number, because the mean of its divisors is an integer number (5202621543).

Almost surely, 2^20808079421 is an apocalyptic number.

It is an amenable number.

20808079421 is a deficient number, since it is larger than the sum of its proper divisors (2406751).

20808079421 is an equidigital number, since it uses as much as digits as its factorization.

20808079421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2406750.

The product of its (nonzero) digits is 64512, while the sum is 41.

The spelling of 20808079421 in words is "twenty billion, eight hundred eight million, seventy-nine thousand, four hundred twenty-one".