21145590 has 32 divisors (see below), whose sum is σ = 56388960. Its totient is φ = 5638752.

The previous prime is 21145583. The next prime is 21145601. The reversal of 21145590 is 9554112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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, 38889 + ... + 39428.

It is an arithmetic number, because the mean of its divisors is an integer number (1762155).

Almost surely, 2^21145590 is an apocalyptic number.

21145590 is an abundant number, since it is smaller than the sum of its proper divisors (35243370).

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

21145590 is a wasteful number, since it uses less digits than its factorization.

21145590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78333 (or 78327 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 21145590 is about 4598.4334288973. The cubic root of 21145590 is about 276.5285241227.

The spelling of 21145590 in words is "twenty-one million, one hundred forty-five thousand, five hundred ninety".