21065590 has 48 divisors (see below), whose sum is σ = 47516112. Its totient is φ = 6664896.

The previous prime is 21065563. The next prime is 21065599. The reversal of 21065590 is 9556012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21065599) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4717 + ... + 8023.

It is an arithmetic number, because the mean of its divisors is an integer number (989919).

Almost surely, 2^21065590 is an apocalyptic number.

21065590 is an abundant number, since it is smaller than the sum of its proper divisors (26450522).

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

21065590 is a wasteful number, since it uses less digits than its factorization.

21065590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3341 (or 3334 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 21065590 is about 4589.7265713766. The cubic root of 21065590 is about 276.1793537742.

The spelling of 21065590 in words is "twenty-one million, sixty-five thousand, five hundred ninety".