16534507221 has 6 divisors (see below), whose sum is σ = 23883177110. Its totient is φ = 11023004808.

The previous prime is 16534507219. The next prime is 16534507247. The reversal of 16534507221 is 12270543561.

16534507221 is a `hidden beast` number, since 1 + 6 + 534 + 50 + 72 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14517599121 + 2016908100 = 120489^2 + 44910^2 .

It is not a de Polignac number, because 16534507221 - 2¹ = 16534507219 is a prime.

It is a super-2 number, since 2×16534507221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16534507261) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 918583726 + ... + 918583743.

Almost surely, 2^16534507221 is an apocalyptic number.

It is an amenable number.

16534507221 is a deficient number, since it is larger than the sum of its proper divisors (7348669889).

16534507221 is a wasteful number, since it uses less digits than its factorization.

16534507221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1837167475 (or 1837167472 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 16534507221 in words is "sixteen billion, five hundred thirty-four million, five hundred seven thousand, two hundred twenty-one".