21245590 has 16 divisors (see below), whose sum is σ = 38427120. Its totient is φ = 8457120.

The previous prime is 21245561. The next prime is 21245617. The reversal of 21245590 is 9554212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2925 + ... + 7144.

It is an arithmetic number, because the mean of its divisors is an integer number (2401695).

Almost surely, 2^21245590 is an apocalyptic number.

21245590 is a deficient number, since it is larger than the sum of its proper divisors (17181530).

21245590 is a wasteful number, since it uses less digits than its factorization.

21245590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10287.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 21245590 is about 4609.2938721674. The cubic root of 21245590 is about 276.9637508118.

The spelling of 21245590 in words is "twenty-one million, two hundred forty-five thousand, five hundred ninety".