21372380 has 12 divisors (see below), whose sum is σ = 44882040. Its totient is φ = 8548944.

The previous prime is 21372367. The next prime is 21372413. The reversal of 21372380 is 8327312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 534290 + ... + 534329.

It is an arithmetic number, because the mean of its divisors is an integer number (3740170).

Almost surely, 2^21372380 is an apocalyptic number.

21372380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21372380 is an abundant number, since it is smaller than the sum of its proper divisors (23509660).

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

21372380 is a wasteful number, since it uses less digits than its factorization.

21372380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1068628 (or 1068626 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21372380 is about 4623.0271467946. The cubic root of 21372380 is about 277.5136156510.

Adding to 21372380 its reverse (8327312), we get a palindrome (29699692).

The spelling of 21372380 in words is "twenty-one million, three hundred seventy-two thousand, three hundred eighty".