21955893 has 4 divisors (see below), whose sum is σ = 29274528. Its totient is φ = 14637260.

The previous prime is 21955889. The next prime is 21955919. The reversal of 21955893 is 39855912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21955893 - 2² = 21955889 is a prime.

It is a super-2 number, since 2×21955893² = 964122474854898, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21955093) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3659313 + ... + 3659318.

It is an arithmetic number, because the mean of its divisors is an integer number (7318632).

Almost surely, 2^21955893 is an apocalyptic number.

It is an amenable number.

21955893 is a deficient number, since it is larger than the sum of its proper divisors (7318635).

21955893 is an equidigital number, since it uses as much as digits as its factorization.

21955893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7318634.

The product of its digits is 97200, while the sum is 42.

The square root of 21955893 is about 4685.7115788320. The cubic root of 21955893 is about 280.0165508924.

The spelling of 21955893 in words is "twenty-one million, nine hundred fifty-five thousand, eight hundred ninety-three".