21854399 has 8 divisors (see below), whose sum is σ = 25082880. Its totient is φ = 18652536.

The previous prime is 21854369. The next prime is 21854419. The reversal of 21854399 is 99345812.

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

It is a de Polignac number, because none of the positive numbers 2^k-21854399 is a prime.

It is a super-2 number, since 2×21854399² = 955229511302402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854369) 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, 4859 + ... + 8204.

It is an arithmetic number, because the mean of its divisors is an integer number (3135360).

Almost surely, 2^21854399 is an apocalyptic number.

21854399 is a deficient number, since it is larger than the sum of its proper divisors (3228481).

21854399 is a wasteful number, since it uses less digits than its factorization.

21854399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13309.

The product of its digits is 77760, while the sum is 41.

The square root of 21854399 is about 4674.8688751664. The cubic root of 21854399 is about 279.5844132372.

The spelling of 21854399 in words is "twenty-one million, eight hundred fifty-four thousand, three hundred ninety-nine".