21238255 has 16 divisors (see below), whose sum is σ = 26682624. Its totient is φ = 16208640.

The previous prime is 21238249. The next prime is 21238271. The reversal of 21238255 is 55283212.

It is not a de Polignac number, because 21238255 - 2⁷ = 21238127 is a prime.

It is a super-3 number, since 3×21238255³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10377 + ... + 12253.

It is an arithmetic number, because the mean of its divisors is an integer number (1667664).

Almost surely, 2^21238255 is an apocalyptic number.

21238255 is a deficient number, since it is larger than the sum of its proper divisors (5444369).

21238255 is a wasteful number, since it uses less digits than its factorization.

21238255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1986.

The product of its digits is 4800, while the sum is 28.

The square root of 21238255 is about 4608.4981284579. The cubic root of 21238255 is about 276.9318734049.

The spelling of 21238255 in words is "twenty-one million, two hundred thirty-eight thousand, two hundred fifty-five".