20902989 has 8 divisors (see below), whose sum is σ = 28550592. Its totient is φ = 13595360.

The previous prime is 20902967. The next prime is 20902993. The reversal of 20902989 is 98920902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20902989 - 2²⁰ = 19854413 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20902949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84849 + ... + 85094.

It is an arithmetic number, because the mean of its divisors is an integer number (3568824).

Almost surely, 2^20902989 is an apocalyptic number.

It is an amenable number.

20902989 is a deficient number, since it is larger than the sum of its proper divisors (7647603).

20902989 is a wasteful number, since it uses less digits than its factorization.

20902989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169987.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 20902989 is about 4571.9786744909. The cubic root of 20902989 is about 275.4669268590.

The spelling of 20902989 in words is "twenty million, nine hundred two thousand, nine hundred eighty-nine".