21002340 has 24 divisors (see below), whose sum is σ = 58806720. Its totient is φ = 5600608.

The previous prime is 21002329. The next prime is 21002341. The reversal of 21002340 is 4320012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21002341) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 174960 + ... + 175079.

It is an arithmetic number, because the mean of its divisors is an integer number (2450280).

Almost surely, 2^21002340 is an apocalyptic number.

21002340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002340 is an abundant number, since it is smaller than the sum of its proper divisors (37804380).

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

21002340 is a wasteful number, since it uses less digits than its factorization.

21002340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350051 (or 350049 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 21002340 is about 4582.8310027755. The cubic root of 21002340 is about 275.9026646902.

Adding to 21002340 its reverse (4320012), we get a palindrome (25322352).

The spelling of 21002340 in words is "twenty-one million, two thousand, three hundred forty".