21239140 has 24 divisors (see below), whose sum is σ = 48033720. Its totient is φ = 7842048.

The previous prime is 21239087. The next prime is 21239173. The reversal of 21239140 is 4193212.

It can be written as a sum of positive squares in 4 ways, for example, as 2903616 + 18335524 = 1704^2 + 4282^2 .

It is a super-2 number, since 2×21239140² = 902202135879200, which contains 22 as substring.

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, 40585 + ... + 41104.

It is an arithmetic number, because the mean of its divisors is an integer number (2001405).

Almost surely, 2^21239140 is an apocalyptic number.

21239140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21239140 is an abundant number, since it is smaller than the sum of its proper divisors (26794580).

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

21239140 is a wasteful number, since it uses less digits than its factorization.

21239140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81711 (or 81709 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21239140 is about 4608.5941457238. The cubic root of 21239140 is about 276.9357199435.

The spelling of 21239140 in words is "twenty-one million, two hundred thirty-nine thousand, one hundred forty".