21837340 has 36 divisors (see below), whose sum is σ = 53347896. Its totient is φ = 7486752.

The previous prime is 21837331. The next prime is 21837341. The reversal of 21837340 is 4373812.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21837299 and 21837308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21837341) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10162 + ... + 12121.

It is an arithmetic number, because the mean of its divisors is an integer number (1481886).

Almost surely, 2^21837340 is an apocalyptic number.

21837340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21837340 is an abundant number, since it is smaller than the sum of its proper divisors (31510556).

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

21837340 is a wasteful number, since it uses less digits than its factorization.

21837340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22306 (or 22297 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21837340 is about 4673.0439758256. The cubic root of 21837340 is about 279.5116487561.

The spelling of 21837340 in words is "twenty-one million, eight hundred thirty-seven thousand, three hundred forty".