21135507 has 8 divisors (see below), whose sum is σ = 28252560. Its totient is φ = 14054400.

The previous prime is 21135503. The next prime is 21135553. The reversal of 21135507 is 70553112.

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

It is not a de Polignac number, because 21135507 - 2² = 21135503 is a prime.

It is a super-2 number, since 2×21135507² = 893419312294098, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21135503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7582 + ... + 9987.

It is an arithmetic number, because the mean of its divisors is an integer number (3531570).

Almost surely, 2^21135507 is an apocalyptic number.

21135507 is a deficient number, since it is larger than the sum of its proper divisors (7117053).

21135507 is a wasteful number, since it uses less digits than its factorization.

21135507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17973.

The product of its (nonzero) digits is 1050, while the sum is 24.

The square root of 21135507 is about 4597.3369465376. The cubic root of 21135507 is about 276.4845641228.

Adding to 21135507 its reverse (70553112), we get a palindrome (91688619).

The spelling of 21135507 in words is "twenty-one million, one hundred thirty-five thousand, five hundred seven".