21368340 has 96 divisors (see below), whose sum is σ = 75989760. Its totient is φ = 4883328.

The previous prime is 21368309. The next prime is 21368353. The reversal of 21368340 is 4386312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 954 + ... + 6606.

It is an arithmetic number, because the mean of its divisors is an integer number (791560).

Almost surely, 2^21368340 is an apocalyptic number.

21368340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21368340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37994880).

21368340 is an abundant number, since it is smaller than the sum of its proper divisors (54621420).

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

21368340 is a wasteful number, since it uses less digits than its factorization.

21368340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5678 (or 5670 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21368340 is about 4622.5901830035. The cubic root of 21368340 is about 277.4961285070.

The spelling of 21368340 in words is "twenty-one million, three hundred sixty-eight thousand, three hundred forty".