21672135 has 24 divisors (see below), whose sum is σ = 38862720. Its totient is φ = 11159232.

The previous prime is 21672109. The next prime is 21672137. The reversal of 21672135 is 53127612.

It is a happy number.

It is not a de Polignac number, because 21672135 - 2⁸ = 21671879 is a prime.

It is a super-3 number, since 3×21672135³ (a number of 23 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21672099 and 21672108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21672137) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6999 + ... + 9608.

It is an arithmetic number, because the mean of its divisors is an integer number (1619280).

Almost surely, 2^21672135 is an apocalyptic number.

21672135 is a deficient number, since it is larger than the sum of its proper divisors (17190585).

21672135 is a wasteful number, since it uses less digits than its factorization.

21672135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16647 (or 16644 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 21672135 is about 4655.3340374242. The cubic root of 21672135 is about 278.8050049979.

Adding to 21672135 its reverse (53127612), we get a palindrome (74799747).

The spelling of 21672135 in words is "twenty-one million, six hundred seventy-two thousand, one hundred thirty-five".