21031340 has 24 divisors (see below), whose sum is σ = 48181392. Its totient is φ = 7647680.

The previous prime is 21031333. The next prime is 21031349. The reversal of 21031340 is 4313012.

It is not an unprimeable number, because it can be changed into a prime (21031349) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 47579 + ... + 48018.

It is an arithmetic number, because the mean of its divisors is an integer number (2007558).

Almost surely, 2^21031340 is an apocalyptic number.

21031340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21031340 is an abundant number, since it is smaller than the sum of its proper divisors (27150052).

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

21031340 is a wasteful number, since it uses less digits than its factorization.

21031340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95617 (or 95615 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21031340 is about 4585.9938944573. The cubic root of 21031340 is about 276.0295949501.

Adding to 21031340 its reverse (4313012), we get a palindrome (25344352).

It can be divided in two parts, 2103 and 1340, that added together give a palindrome (3443).

The spelling of 21031340 in words is "twenty-one million, thirty-one thousand, three hundred forty".