20456989 has 8 divisors (see below), whose sum is σ = 23524160. Its totient is φ = 17426016.

The previous prime is 20456987. The next prime is 20457023. The reversal of 20456989 is 98965402.

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 20456989 - 2¹ = 20456987 is a prime.

It is a super-2 number, since 2×20456989² = 836976797892242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20456981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7824 + ... + 10105.

It is an arithmetic number, because the mean of its divisors is an integer number (2940520).

Almost surely, 2^20456989 is an apocalyptic number.

It is an amenable number.

20456989 is a deficient number, since it is larger than the sum of its proper divisors (3067171).

20456989 is a wasteful number, since it uses less digits than its factorization.

20456989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18099.

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 20456989 is about 4522.9403047133. The cubic root of 20456989 is about 273.4936436486.

The spelling of 20456989 in words is "twenty million, four hundred fifty-six thousand, nine hundred eighty-nine".