21517337353 has 4 divisors (see below), whose sum is σ = 21519077140. Its totient is φ = 21515597568.

The previous prime is 21517337329. The next prime is 21517337381. The reversal of 21517337353 is 35373371512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9388059664 + 12129277689 = 96892^2 + 110133^2 .

It is a cyclic number.

It is not a de Polignac number, because 21517337353 - 2¹⁷ = 21517206281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21517397353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 851208 + ... + 876121.

It is an arithmetic number, because the mean of its divisors is an integer number (5379769285).

Almost surely, 2^21517337353 is an apocalyptic number.

It is an amenable number.

21517337353 is a deficient number, since it is larger than the sum of its proper divisors (1739787).

21517337353 is a wasteful number, since it uses less digits than its factorization.

21517337353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1739786.

The product of its digits is 198450, while the sum is 40.

The spelling of 21517337353 in words is "twenty-one billion, five hundred seventeen million, three hundred thirty-seven thousand, three hundred fifty-three".