21232340 has 12 divisors (see below), whose sum is σ = 44587956. Its totient is φ = 8492928.

The previous prime is 21232307. The next prime is 21232363. The reversal of 21232340 is 4323212.

It can be written as a sum of positive squares in 2 ways, for example, as 4813636 + 16418704 = 2194^2 + 4052^2 .

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, 530789 + ... + 530828.

It is an arithmetic number, because the mean of its divisors is an integer number (3715663).

Almost surely, 2^21232340 is an apocalyptic number.

21232340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21232340 is an abundant number, since it is smaller than the sum of its proper divisors (23355616).

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

21232340 is a wasteful number, since it uses less digits than its factorization.

21232340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061626 (or 1061624 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21232340 is about 4607.8563345660. The cubic root of 21232340 is about 276.9061618744.

Adding to 21232340 its reverse (4323212), we get a palindrome (25555552).

The spelling of 21232340 in words is "twenty-one million, two hundred thirty-two thousand, three hundred forty".