21516060571 has 4 divisors (see below), whose sum is σ = 21922024032. Its totient is φ = 21110097112.

The previous prime is 21516060551. The next prime is 21516060583. The reversal of 21516060571 is 17506061512.

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

It is a cyclic number.

It is not a de Polignac number, because 21516060571 - 2⁷ = 21516060443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21516060551) 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, 202981651 + ... + 202981756.

It is an arithmetic number, because the mean of its divisors is an integer number (5480506008).

Almost surely, 2^21516060571 is an apocalyptic number.

21516060571 is a deficient number, since it is larger than the sum of its proper divisors (405963461).

21516060571 is an equidigital number, since it uses as much as digits as its factorization.

21516060571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405963460.

The product of its (nonzero) digits is 12600, while the sum is 34.

The spelling of 21516060571 in words is "twenty-one billion, five hundred sixteen million, sixty thousand, five hundred seventy-one".