21906135 has 24 divisors (see below), whose sum is σ = 38857104. Its totient is φ = 11410560.

The previous prime is 21906113. The next prime is 21906151. The reversal of 21906135 is 53160912.

It is not a de Polignac number, because 21906135 - 2⁷ = 21906007 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21906099 and 21906108.

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 23 ways as a sum of consecutive naturals, for example, 3726 + ... + 7595.

It is an arithmetic number, because the mean of its divisors is an integer number (1619046).

Almost surely, 2^21906135 is an apocalyptic number.

21906135 is a deficient number, since it is larger than the sum of its proper divisors (16950969).

21906135 is a wasteful number, since it uses less digits than its factorization.

21906135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11375 (or 11372 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21906135 is about 4680.3990214511. The cubic root of 21906135 is about 279.8048597809.

The spelling of 21906135 in words is "twenty-one million, nine hundred six thousand, one hundred thirty-five".