21182855 has 16 divisors (see below), whose sum is σ = 26224128. Its totient is φ = 16416000.

The previous prime is 21182849. The next prime is 21182857. The reversal of 21182855 is 55828112.

It is a happy number.

It is not a de Polignac number, because 21182855 - 2¹⁴ = 21166471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21182857) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38885 + ... + 39425.

It is an arithmetic number, because the mean of its divisors is an integer number (1639008).

Almost surely, 2^21182855 is an apocalyptic number.

21182855 is a deficient number, since it is larger than the sum of its proper divisors (5041273).

21182855 is a wasteful number, since it uses less digits than its factorization.

21182855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778.

The product of its digits is 6400, while the sum is 32.

The square root of 21182855 is about 4602.4835686833. The cubic root of 21182855 is about 276.6908714166.

The spelling of 21182855 in words is "twenty-one million, one hundred eighty-two thousand, eight hundred fifty-five".