21112399 has 8 divisors (see below), whose sum is σ = 26322048. Its totient is φ = 16451160.

The previous prime is 21112381. The next prime is 21112411. The reversal of 21112399 is 99321112.

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

It is not a de Polignac number, because 21112399 - 2¹⁵ = 21079631 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112339) 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, 137017 + ... + 137170.

It is an arithmetic number, because the mean of its divisors is an integer number (3290256).

Almost surely, 2^21112399 is an apocalyptic number.

21112399 is a deficient number, since it is larger than the sum of its proper divisors (5209649).

21112399 is a wasteful number, since it uses less digits than its factorization.

21112399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274205.

The product of its digits is 972, while the sum is 28.

The square root of 21112399 is about 4594.8230651463. The cubic root of 21112399 is about 276.3837647879.

The spelling of 21112399 in words is "twenty-one million, one hundred twelve thousand, three hundred ninety-nine".