21255118 has 16 divisors (see below), whose sum is σ = 32527440. Its totient is φ = 10414656.

The previous prime is 21255107. The next prime is 21255127. The reversal of 21255118 is 81155212.

It is a junction number, because it is equal to n+sod(n) for n = 21255092 and 21255101.

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, 28393 + ... + 29131.

It is an arithmetic number, because the mean of its divisors is an integer number (2032965).

Almost surely, 2^21255118 is an apocalyptic number.

21255118 is a deficient number, since it is larger than the sum of its proper divisors (11272322).

21255118 is a wasteful number, since it uses less digits than its factorization.

21255118 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011.

The product of its digits is 800, while the sum is 25.

The square root of 21255118 is about 4610.3273202670. The cubic root of 21255118 is about 277.0051478927.

The spelling of 21255118 in words is "twenty-one million, two hundred fifty-five thousand, one hundred eighteen".