21940855 has 4 divisors (see below), whose sum is σ = 26329032. Its totient is φ = 17552680.

The previous prime is 21940843. The next prime is 21940909. The reversal of 21940855 is 55804912.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21940855 - 2⁵ = 21940823 is a prime.

It is a super-2 number, since 2×21940855² = 962802236262050, 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 21940855.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2194081 + ... + 2194090.

It is an arithmetic number, because the mean of its divisors is an integer number (6582258).

Almost surely, 2^21940855 is an apocalyptic number.

21940855 is a deficient number, since it is larger than the sum of its proper divisors (4388177).

21940855 is an equidigital number, since it uses as much as digits as its factorization.

21940855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4388176.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 21940855 is about 4684.1066384104. The cubic root of 21940855 is about 279.9526067745.

The spelling of 21940855 in words is "twenty-one million, nine hundred forty thousand, eight hundred fifty-five".