21140340 has 48 divisors (see below), whose sum is σ = 63748608. Its totient is φ = 5203584.

The previous prime is 21140303. The next prime is 21140341. The reversal of 21140340 is 4304112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21140341) 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 15 ways as a sum of consecutive naturals, for example, 12772 + ... + 14331.

It is an arithmetic number, because the mean of its divisors is an integer number (1328096).

Almost surely, 2^21140340 is an apocalyptic number.

21140340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21140340 is an abundant number, since it is smaller than the sum of its proper divisors (42608268).

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

21140340 is a wasteful number, since it uses less digits than its factorization.

21140340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27128 (or 27126 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21140340 is about 4597.8625468798. The cubic root of 21140340 is about 276.5056368458.

Adding to 21140340 its reverse (4304112), we get a palindrome (25444452).

The spelling of 21140340 in words is "twenty-one million, one hundred forty thousand, three hundred forty".