21213135 has 12 divisors (see below), whose sum is σ = 36769512. Its totient is φ = 11313648.

The previous prime is 21213119. The next prime is 21213149. The reversal of 21213135 is 53131212.

It is not a de Polignac number, because 21213135 - 2⁴ = 21213119 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 235657 + ... + 235746.

It is an arithmetic number, because the mean of its divisors is an integer number (3064126).

Almost surely, 2^21213135 is an apocalyptic number.

21213135 is a deficient number, since it is larger than the sum of its proper divisors (15556377).

21213135 is a wasteful number, since it uses less digits than its factorization.

21213135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471414 (or 471411 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21213135 is about 4605.7719222732. The cubic root of 21213135 is about 276.8226479667.

Adding to 21213135 its reverse (53131212), we get a palindrome (74344347).

The spelling of 21213135 in words is "twenty-one million, two hundred thirteen thousand, one hundred thirty-five".