21045490 has 32 divisors (see below), whose sum is σ = 41057280. Its totient is φ = 7736064.

The previous prime is 21045487. The next prime is 21045517. The reversal of 21045490 is 9454012.

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, 5871 + ... + 8749.

It is an arithmetic number, because the mean of its divisors is an integer number (1283040).

Almost surely, 2^21045490 is an apocalyptic number.

21045490 is a deficient number, since it is larger than the sum of its proper divisors (20011790).

21045490 is a wasteful number, since it uses less digits than its factorization.

21045490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2946.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21045490 is about 4587.5363758776. The cubic root of 21045490 is about 276.0914858099.

The spelling of 21045490 in words is "twenty-one million, forty-five thousand, four hundred ninety".