21240330 has 16 divisors (see below), whose sum is σ = 50976864. Its totient is φ = 5664080.

The previous prime is 21240313. The next prime is 21240377. The reversal of 21240330 is 3304212.

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

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 353976 + ... + 354035.

It is an arithmetic number, because the mean of its divisors is an integer number (3186054).

Almost surely, 2^21240330 is an apocalyptic number.

21240330 is an abundant number, since it is smaller than the sum of its proper divisors (29736534).

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

21240330 is a wasteful number, since it uses less digits than its factorization.

21240330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708021.

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

The square root of 21240330 is about 4608.7232505326. The cubic root of 21240330 is about 276.9408919569.

Adding to 21240330 its reverse (3304212), we get a palindrome (24544542).

The spelling of 21240330 in words is "twenty-one million, two hundred forty thousand, three hundred thirty".