21030140 has 12 divisors (see below), whose sum is σ = 44163336. Its totient is φ = 8412048.

The previous prime is 21030127. The next prime is 21030181. The reversal of 21030140 is 4103012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525734 + ... + 525773.

It is an arithmetic number, because the mean of its divisors is an integer number (3680278).

Almost surely, 2^21030140 is an apocalyptic number.

21030140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21030140 is an abundant number, since it is smaller than the sum of its proper divisors (23133196).

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

21030140 is a wasteful number, since it uses less digits than its factorization.

21030140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051516 (or 1051514 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21030140 is about 4585.8630594469. The cubic root of 21030140 is about 276.0243449785.

Adding to 21030140 its reverse (4103012), we get a palindrome (25133152).

The spelling of 21030140 in words is "twenty-one million, thirty thousand, one hundred forty".