20989320479 has 4 divisors (see below), whose sum is σ = 21255008160. Its totient is φ = 20723632800.

The previous prime is 20989320467. The next prime is 20989320511. The reversal of 20989320479 is 97402398902.

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 20989320479 - 2¹⁶ = 20989254943 is a prime.

It is a super-3 number, since 3×20989320479³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20989320479.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989320179) 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, 132843722 + ... + 132843879.

It is an arithmetic number, because the mean of its divisors is an integer number (5313752040).

Almost surely, 2^20989320479 is an apocalyptic number.

20989320479 is a deficient number, since it is larger than the sum of its proper divisors (265687681).

20989320479 is an equidigital number, since it uses as much as digits as its factorization.

20989320479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265687680.

The product of its (nonzero) digits is 1959552, while the sum is 53.

The spelling of 20989320479 in words is "twenty billion, nine hundred eighty-nine million, three hundred twenty thousand, four hundred seventy-nine".