16605250021 has 16 divisors (see below), whose sum is σ = 17668219824. Its totient is φ = 15552036864.

The previous prime is 16605250003. The next prime is 16605250033. The reversal of 16605250021 is 12005250661.

It can be written as a sum of positive squares in 8 ways, for example, as 2801584900 + 13803665121 = 52930^2 + 117489^2 .

It is a cyclic number.

It is not a de Polignac number, because 16605250021 - 2⁵ = 16605249989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16605250121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3578715 + ... + 3583351.

It is an arithmetic number, because the mean of its divisors is an integer number (1104263739).

Almost surely, 2^16605250021 is an apocalyptic number.

It is an amenable number.

16605250021 is a deficient number, since it is larger than the sum of its proper divisors (1062969803).

16605250021 is a wasteful number, since it uses less digits than its factorization.

16605250021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5640.

The product of its (nonzero) digits is 3600, while the sum is 28.

The spelling of 16605250021 in words is "sixteen billion, six hundred five million, two hundred fifty thousand, twenty-one".