21913855 has 8 divisors (see below), whose sum is σ = 26378064. Its totient is φ = 17476800.

The previous prime is 21913849. The next prime is 21913861. The reversal of 21913855 is 55831912.

It is an interprime number because it is at equal distance from previous prime (21913849) and next prime (21913861).

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

It is not a de Polignac number, because 21913855 - 2⁹ = 21913343 is a prime.

It is a super-2 number, since 2×21913855² = 960434081922050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21913855.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4966 + ... + 8275.

It is an arithmetic number, because the mean of its divisors is an integer number (3297258).

Almost surely, 2^21913855 is an apocalyptic number.

21913855 is a deficient number, since it is larger than the sum of its proper divisors (4464209).

21913855 is a wasteful number, since it uses less digits than its factorization.

21913855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13577.

The product of its digits is 10800, while the sum is 34.

The square root of 21913855 is about 4681.2236648124. The cubic root of 21913855 is about 279.8377248485.

The spelling of 21913855 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred fifty-five".