21455530 has 32 divisors (see below), whose sum is σ = 41582160. Its totient is φ = 7941120.

The previous prime is 21455521. The next prime is 21455537. The reversal of 21455530 is 3555412.

It can be written as a sum of positive squares in 8 ways, for example, as 2819041 + 18636489 = 1679^2 + 4317^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21455495 and 21455504.

It is not an unprimeable number, because it can be changed into a prime (21455537) 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, 9336 + ... + 11404.

Almost surely, 2^21455530 is an apocalyptic number.

21455530 is a deficient number, since it is larger than the sum of its proper divisors (20126630).

21455530 is a wasteful number, since it uses less digits than its factorization.

21455530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2154.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 21455530 is about 4632.0114421275. The cubic root of 21455530 is about 277.8730421104.

The spelling of 21455530 in words is "twenty-one million, four hundred fifty-five thousand, five hundred thirty".