21372534 has 12 divisors (see below), whose sum is σ = 46307196. Its totient is φ = 7124172.

The previous prime is 21372529. The next prime is 21372539. The reversal of 21372534 is 43527312.

It is an interprime number because it is at equal distance from previous prime (21372529) and next prime (21372539).

It is a junction number, because it is equal to n+sod(n) for n = 21372498 and 21372507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21372539) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 593664 + ... + 593699.

It is an arithmetic number, because the mean of its divisors is an integer number (3858933).

Almost surely, 2^21372534 is an apocalyptic number.

21372534 is an abundant number, since it is smaller than the sum of its proper divisors (24934662).

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

21372534 is a wasteful number, since it uses less digits than its factorization.

21372534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187371 (or 1187368 counting only the distinct ones).

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

The square root of 21372534 is about 4623.0438025180. The cubic root of 21372534 is about 277.5142821965.

Adding to 21372534 its reverse (43527312), we get a palindrome (64899846).

The spelling of 21372534 in words is "twenty-one million, three hundred seventy-two thousand, five hundred thirty-four".