20979175669 has 4 divisors (see below), whose sum is σ = 22213244844. Its totient is φ = 19745106496.

The previous prime is 20979175663. The next prime is 20979175681. The reversal of 20979175669 is 96657197902.

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 8870814225 + 12108361444 = 94185^2 + 110038^2 .

It is a cyclic number.

It is not a de Polignac number, because 20979175669 - 2³ = 20979175661 is a prime.

It is a super-2 number, since 2×20979175669² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20979175661) 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, 617034562 + ... + 617034595.

It is an arithmetic number, because the mean of its divisors is an integer number (5553311211).

Almost surely, 2^20979175669 is an apocalyptic number.

It is an amenable number.

20979175669 is a deficient number, since it is larger than the sum of its proper divisors (1234069175).

20979175669 is a wasteful number, since it uses less digits than its factorization.

20979175669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234069174.

The product of its (nonzero) digits is 12859560, while the sum is 61.

The spelling of 20979175669 in words is "twenty billion, nine hundred seventy-nine million, one hundred seventy-five thousand, six hundred sixty-nine".