21615450 has 24 divisors (see below), whose sum is σ = 53606688. Its totient is φ = 5764080.

The previous prime is 21615413. The next prime is 21615457. The reversal of 21615450 is 5451612.

It is a self number, because there is not a number n which added to its sum of digits gives 21615450.

It is not an unprimeable number, because it can be changed into a prime (21615457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 71902 + ... + 72201.

It is an arithmetic number, because the mean of its divisors is an integer number (2233612).

Almost surely, 2^21615450 is an apocalyptic number.

21615450 is an abundant number, since it is smaller than the sum of its proper divisors (31991238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21615450 is a wasteful number, since it uses less digits than its factorization.

21615450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144118 (or 144113 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 21615450 is about 4649.2418736822. The cubic root of 21615450 is about 278.5617146984.

The spelling of 21615450 in words is "twenty-one million, six hundred fifteen thousand, four hundred fifty".