21042330 has 32 divisors (see below), whose sum is σ = 50670144. Its totient is φ = 5592576.

The previous prime is 21042319. The next prime is 21042347. The reversal of 21042330 is 3324012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a Curzon number.

It is a plaindrome in base 13.

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, 9597 + ... + 11583.

It is an arithmetic number, because the mean of its divisors is an integer number (1583442).

Almost surely, 2^21042330 is an apocalyptic number.

21042330 is an abundant number, since it is smaller than the sum of its proper divisors (29627814).

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

21042330 is a wasteful number, since it uses less digits than its factorization.

21042330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2350.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21042330 is about 4587.1919515102. The cubic root of 21042330 is about 276.0776666533.

Adding to 21042330 its reverse (3324012), we get a palindrome (24366342).

The spelling of 21042330 in words is "twenty-one million, forty-two thousand, three hundred thirty".