21370140 has 144 divisors (see below), whose sum is σ = 72648576. Its totient is φ = 5040000.

The previous prime is 21370133. The next prime is 21370157. The reversal of 21370140 is 4107312.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85015 + ... + 85265.

It is an arithmetic number, because the mean of its divisors is an integer number (504504).

Almost surely, 2^21370140 is an apocalyptic number.

21370140 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 21370140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36324288).

21370140 is an abundant number, since it is smaller than the sum of its proper divisors (51278436).

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

21370140 is a wasteful number, since it uses less digits than its factorization.

21370140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320 (or 315 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21370140 is about 4622.7848749428. The cubic root of 21370140 is about 277.5039200810.

Adding to 21370140 its reverse (4107312), we get a palindrome (25477452).

The spelling of 21370140 in words is "twenty-one million, three hundred seventy thousand, one hundred forty".