20845979 has 16 divisors (see below), whose sum is σ = 26267136. Its totient is φ = 16070400.

The previous prime is 20845963. The next prime is 20845991. The reversal of 20845979 is 97954802.

20845979 = T₆₉₇ + T₆₉₈ + ... + T₇₇₃.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20845979 - 2⁴ = 20845963 is a prime.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20845579) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6074 + ... + 8864.

It is an arithmetic number, because the mean of its divisors is an integer number (1641696).

Almost surely, 2^20845979 is an apocalyptic number.

20845979 is a deficient number, since it is larger than the sum of its proper divisors (5421157).

20845979 is a wasteful number, since it uses less digits than its factorization.

20845979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2906.

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 20845979 is about 4565.7396991068. The cubic root of 20845979 is about 275.2162662424.

The spelling of 20845979 in words is "twenty million, eight hundred forty-five thousand, nine hundred seventy-nine".