21517130 has 16 divisors (see below), whose sum is σ = 40066920. Its totient is φ = 8309952.

The previous prime is 21517127. The next prime is 21517163. The reversal of 21517130 is 3171512.

It can be written as a sum of positive squares in 4 ways, for example, as 10220809 + 11296321 = 3197^2 + 3361^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36809 + ... + 37388.

Almost surely, 2^21517130 is an apocalyptic number.

21517130 is a deficient number, since it is larger than the sum of its proper divisors (18549790).

21517130 is a wasteful number, since it uses less digits than its factorization.

21517130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74233.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21517130 is about 4638.6560553678. The cubic root of 21517130 is about 278.1387175829.

Adding to 21517130 its reverse (3171512), we get a palindrome (24688642).

The spelling of 21517130 in words is "twenty-one million, five hundred seventeen thousand, one hundred thirty".