21240310 has 64 divisors (see below), whose sum is σ = 49859712. Its totient is φ = 6322176.

The previous prime is 21240283. The next prime is 21240311. The reversal of 21240310 is 1304212.

It is a super-2 number, since 2×21240310² = 902301537792200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240311) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14784 + ... + 16156.

It is an arithmetic number, because the mean of its divisors is an integer number (779058).

Almost surely, 2^21240310 is an apocalyptic number.

21240310 is an abundant number, since it is smaller than the sum of its proper divisors (28619402).

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

21240310 is a wasteful number, since it uses less digits than its factorization.

21240310 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21240310 is about 4608.7210807338. The cubic root of 21240310 is about 276.9408050339.

Adding to 21240310 its reverse (1304212), we get a palindrome (22544522).

The spelling of 21240310 in words is "twenty-one million, two hundred forty thousand, three hundred ten".