21372135 has 8 divisors (see below), whose sum is σ = 34195440. Its totient is φ = 11398464.

The previous prime is 21372133. The next prime is 21372149. The reversal of 21372135 is 53127312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21372135 - 2¹ = 21372133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21372133) 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 7 ways as a sum of consecutive naturals, for example, 712390 + ... + 712419.

It is an arithmetic number, because the mean of its divisors is an integer number (4274430).

Almost surely, 2^21372135 is an apocalyptic number.

21372135 is a deficient number, since it is larger than the sum of its proper divisors (12823305).

21372135 is a wasteful number, since it uses less digits than its factorization.

21372135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1424817.

The product of its digits is 1260, while the sum is 24.

The square root of 21372135 is about 4623.0006489292. Note that the first 3 decimals coincide. The cubic root of 21372135 is about 277.5125552310.

Adding to 21372135 its reverse (53127312), we get a palindrome (74499447).

The spelling of 21372135 in words is "twenty-one million, three hundred seventy-two thousand, one hundred thirty-five".