21456530 has 32 divisors (see below), whose sum is σ = 40279680. Its totient is φ = 8222080.

The previous prime is 21456521. The next prime is 21456563. The reversal of 21456530 is 3565412.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 21456530.

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, 23747 + ... + 24633.

It is an arithmetic number, because the mean of its divisors is an integer number (1258740).

Almost surely, 2^21456530 is an apocalyptic number.

21456530 is a deficient number, since it is larger than the sum of its proper divisors (18823150).

21456530 is a wasteful number, since it uses less digits than its factorization.

21456530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21456530 is about 4632.1193853354. The cubic root of 21456530 is about 277.8773590817.

The spelling of 21456530 in words is "twenty-one million, four hundred fifty-six thousand, five hundred thirty".