21537135 has 12 divisors (see below), whose sum is σ = 37331112. Its totient is φ = 11486448.

The previous prime is 21537121. The next prime is 21537137. The reversal of 21537135 is 53173512.

It is not a de Polignac number, because 21537135 - 2⁴ = 21537119 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21537099 and 21537108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21537137) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239257 + ... + 239346.

It is an arithmetic number, because the mean of its divisors is an integer number (3110926).

Almost surely, 2^21537135 is an apocalyptic number.

21537135 is a deficient number, since it is larger than the sum of its proper divisors (15793977).

21537135 is a wasteful number, since it uses less digits than its factorization.

21537135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478614 (or 478611 counting only the distinct ones).

The product of its digits is 3150, while the sum is 27.

The square root of 21537135 is about 4640.8118901761. The cubic root of 21537135 is about 278.2248883308.

The spelling of 21537135 in words is "twenty-one million, five hundred thirty-seven thousand, one hundred thirty-five".