21345372 has 36 divisors (see below), whose sum is σ = 55215160. Its totient is φ = 6949152.

The previous prime is 21345371. The next prime is 21345383. The reversal of 21345372 is 27354312.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345371) 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, 5347 + ... + 8442.

Almost surely, 2^21345372 is an apocalyptic number.

It is an amenable number.

21345372 is an abundant number, since it is smaller than the sum of its proper divisors (33869788).

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

21345372 is a wasteful number, since it uses less digits than its factorization.

21345372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13842 (or 13837 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 21345372 is about 4620.1051936076. The cubic root of 21345372 is about 277.3966695879.

Adding to 21345372 its reverse (27354312), we get a palindrome (48699684).

The spelling of 21345372 in words is "twenty-one million, three hundred forty-five thousand, three hundred seventy-two".