20705979 has 24 divisors (see below), whose sum is σ = 32540160. Its totient is φ = 11675664.

The previous prime is 20705947. The next prime is 20705981. The reversal of 20705979 is 97950702.

It is not a de Polignac number, because 20705979 - 2⁵ = 20705947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20705929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10722 + ... + 12504.

It is an arithmetic number, because the mean of its divisors is an integer number (1355840).

Almost surely, 2^20705979 is an apocalyptic number.

20705979 is a deficient number, since it is larger than the sum of its proper divisors (11834181).

20705979 is a wasteful number, since it uses less digits than its factorization.

20705979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1879 (or 1872 counting only the distinct ones).

The product of its (nonzero) digits is 39690, while the sum is 39.

The square root of 20705979 is about 4550.3822916322. The cubic root of 20705979 is about 274.5987713606.

The spelling of 20705979 in words is "twenty million, seven hundred five thousand, nine hundred seventy-nine".