16521687572 has 24 divisors (see below), whose sum is σ = 31458036456. Its totient is φ = 7546779648.

The previous prime is 16521687569. The next prime is 16521687593. The reversal of 16521687572 is 27578612561.

It can be written as a sum of positive squares in 4 ways, for example, as 890186896 + 15631500676 = 29836^2 + 125026^2 .

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 16521687572.

It is a congruent number.

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, 1632713 + ... + 1642800.

It is an arithmetic number, because the mean of its divisors is an integer number (1310751519).

Almost surely, 2^16521687572 is an apocalyptic number.

It is an amenable number.

16521687572 is a deficient number, since it is larger than the sum of its proper divisors (14936348884).

16521687572 is a wasteful number, since it uses less digits than its factorization.

16521687572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3275627 (or 3275625 counting only the distinct ones).

The product of its digits is 1411200, while the sum is 50.

The spelling of 16521687572 in words is "sixteen billion, five hundred twenty-one million, six hundred eighty-seven thousand, five hundred seventy-two".