21416604521 has 8 divisors (see below), whose sum is σ = 23130126600. Its totient is φ = 19712524032.

The previous prime is 21416604511. The next prime is 21416604527. The reversal of 21416604521 is 12540661412.

It can be written as a sum of positive squares in 4 ways, for example, as 5481329296 + 15935275225 = 74036^2 + 126235^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21416604521 - 2¹⁰ = 21416603497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21416604527) 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, 2355680 + ... + 2364753.

It is an arithmetic number, because the mean of its divisors is an integer number (2891265825).

Almost surely, 2^21416604521 is an apocalyptic number.

It is an amenable number.

21416604521 is a deficient number, since it is larger than the sum of its proper divisors (1713522079).

21416604521 is a wasteful number, since it uses less digits than its factorization.

21416604521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4720795.

The product of its (nonzero) digits is 11520, while the sum is 32.

The spelling of 21416604521 in words is "twenty-one billion, four hundred sixteen million, six hundred four thousand, five hundred twenty-one".