16521994 has 8 divisors (see below), whose sum is σ = 26240868. Its totient is φ = 7775040.

The previous prime is 16521991. The next prime is 16522003. The reversal of 16521994 is 49912561.

16521994 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 13227769 + 3294225 = 3637^2 + 1815^2 .

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

It is not an unprimeable number, because it can be changed into a prime (16521991) 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, 242937 + ... + 243004.

Almost surely, 2^16521994 is an apocalyptic number.

16521994 is a deficient number, since it is larger than the sum of its proper divisors (9718874).

16521994 is a wasteful number, since it uses less digits than its factorization.

16521994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 485960.

The product of its digits is 19440, while the sum is 37.

The square root of 16521994 is about 4064.7255749927. The cubic root of 16521994 is about 254.6952350317.

The spelling of 16521994 in words is "sixteen million, five hundred twenty-one thousand, nine hundred ninety-four".