21230790 has 128 divisors (see below), whose sum is σ = 65111040. Its totient is φ = 4313088.

The previous prime is 21230789. The next prime is 21230791. The reversal of 21230790 is 9703212.

It is an interprime number because it is at equal distance from previous prime (21230789) and next prime (21230791).

It is a self number, because there is not a number n which added to its sum of digits gives 21230790.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 67674 + ... + 67986.

It is an arithmetic number, because the mean of its divisors is an integer number (508680).

Almost surely, 2^21230790 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21230790, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32555520).

21230790 is an abundant number, since it is smaller than the sum of its proper divisors (43880250).

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

21230790 is a wasteful number, since it uses less digits than its factorization.

21230790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 21230790 is about 4607.6881404887. The cubic root of 21230790 is about 276.8994234901.

The spelling of 21230790 in words is "twenty-one million, two hundred thirty thousand, seven hundred ninety".