20438999 has 16 divisors (see below), whose sum is σ = 23912448. Its totient is φ = 17109792.

The previous prime is 20438989. The next prime is 20439007. The reversal of 20438999 is 99983402.

It is a de Polignac number, because none of the positive numbers 2^k-20438999 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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20438909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73649 + ... + 73925.

It is an arithmetic number, because the mean of its divisors is an integer number (1494528).

Almost surely, 2^20438999 is an apocalyptic number.

20438999 is a deficient number, since it is larger than the sum of its proper divisors (3473449).

20438999 is a wasteful number, since it uses less digits than its factorization.

20438999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 20438999 is about 4520.9511167452. The cubic root of 20438999 is about 273.4134494809.

The spelling of 20438999 in words is "twenty million, four hundred thirty-eight thousand, nine hundred ninety-nine".