20899955 has 16 divisors (see below), whose sum is σ = 25855200. Its totient is φ = 16208640.

The previous prime is 20899951. The next prime is 20899961. The reversal of 20899955 is 55999802.

It is not a de Polignac number, because 20899955 - 2² = 20899951 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20899951) 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, 54956 + ... + 55334.

It is an arithmetic number, because the mean of its divisors is an integer number (1615950).

Almost surely, 2^20899955 is an apocalyptic number.

20899955 is a deficient number, since it is larger than the sum of its proper divisors (4955245).

20899955 is a wasteful number, since it uses less digits than its factorization.

20899955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694.

The product of its (nonzero) digits is 291600, while the sum is 47.

The square root of 20899955 is about 4571.6468586276. The cubic root of 20899955 is about 275.4535985084.

The spelling of 20899955 in words is "twenty million, eight hundred ninety-nine thousand, nine hundred fifty-five".