21858369 has 8 divisors (see below), whose sum is σ = 31386432. Its totient is φ = 13451280.

The previous prime is 21858301. The next prime is 21858383. The reversal of 21858369 is 96385812.

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

It is not a de Polignac number, because 21858369 - 2¹³ = 21850177 is a prime.

It is a super-2 number, since 2×21858369² = 955576590680322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21858369.

It is not an unprimeable number, because it can be changed into a prime (21858269) 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, 280197 + ... + 280274.

It is an arithmetic number, because the mean of its divisors is an integer number (3923304).

Almost surely, 2^21858369 is an apocalyptic number.

It is an amenable number.

21858369 is a deficient number, since it is larger than the sum of its proper divisors (9528063).

21858369 is a wasteful number, since it uses less digits than its factorization.

21858369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 560487.

The product of its digits is 103680, while the sum is 42.

The square root of 21858369 is about 4675.2934667248. The cubic root of 21858369 is about 279.6013416814.

The spelling of 21858369 in words is "twenty-one million, eight hundred fifty-eight thousand, three hundred sixty-nine".