21143140 has 12 divisors (see below), whose sum is σ = 44400636. Its totient is φ = 8457248.

The previous prime is 21143137. The next prime is 21143179. The reversal of 21143140 is 4134112.

It can be written as a sum of positive squares in 2 ways, for example, as 11669056 + 9474084 = 3416^2 + 3078^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 528559 + ... + 528598.

It is an arithmetic number, because the mean of its divisors is an integer number (3700053).

Almost surely, 2^21143140 is an apocalyptic number.

21143140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21143140 is an abundant number, since it is smaller than the sum of its proper divisors (23257496).

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

21143140 is a wasteful number, since it uses less digits than its factorization.

21143140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1057166 (or 1057164 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21143140 is about 4598.1670261094. The cubic root of 21143140 is about 276.5178438650.

Adding to 21143140 its reverse (4134112), we get a palindrome (25277252).

Subtracting from 21143140 its reverse (4134112), we obtain a triangular number (17009028 = T₅₈₃₂).

The spelling of 21143140 in words is "twenty-one million, one hundred forty-three thousand, one hundred forty".