20890779 has 32 divisors (see below), whose sum is σ = 34890240. Its totient is φ = 10824192.

The previous prime is 20890763. The next prime is 20890781. The reversal of 20890779 is 97709802.

It is not a de Polignac number, because 20890779 - 2⁴ = 20890763 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20890779.

It is not an unprimeable number, because it can be changed into a prime (20890789) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15459 + ... + 16755.

It is an arithmetic number, because the mean of its divisors is an integer number (1090320).

Almost surely, 2^20890779 is an apocalyptic number.

20890779 is a deficient number, since it is larger than the sum of its proper divisors (13999461).

20890779 is a wasteful number, since it uses less digits than its factorization.

20890779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1379.

The product of its (nonzero) digits is 63504, while the sum is 42.

The square root of 20890779 is about 4570.6431713710. The cubic root of 20890779 is about 275.4132805235.

The spelling of 20890779 in words is "twenty million, eight hundred ninety thousand, seven hundred seventy-nine".