21023590 has 32 divisors (see below), whose sum is σ = 43467840. Its totient is φ = 7171584.

The previous prime is 21023573. The next prime is 21023591. The reversal of 21023590 is 9532012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023591) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 15666 + ... + 16954.

It is an arithmetic number, because the mean of its divisors is an integer number (1358370).

Almost surely, 2^21023590 is an apocalyptic number.

21023590 is an abundant number, since it is smaller than the sum of its proper divisors (22444250).

21023590 is a wasteful number, since it uses less digits than its factorization.

21023590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1536.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 21023590 is about 4585.1488525456. The cubic root of 21023590 is about 275.9956853628.

The spelling of 21023590 in words is "twenty-one million, twenty-three thousand, five hundred ninety".