16661631 has 32 divisors (see below), whose sum is σ = 26611200. Its totient is φ = 9072000.

The previous prime is 16661629. The next prime is 16661681. The reversal of 16661631 is 13616661.

16661631 is nontrivially palindromic in base 2.

It is not a de Polignac number, because 16661631 - 2¹ = 16661629 is a prime.

It is a super-2 number, since 2×16661631² = 555219895160322, which contains 22 as substring.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16661681) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66256 + ... + 66506.

It is an arithmetic number, because the mean of its divisors is an integer number (831600).

Almost surely, 2^16661631 is an apocalyptic number.

16661631 is a deficient number, since it is larger than the sum of its proper divisors (9949569).

16661631 is a wasteful number, since it uses less digits than its factorization.

16661631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399.

The product of its digits is 3888, while the sum is 30.

The square root of 16661631 is about 4081.8661173537. The cubic root of 16661631 is about 255.4107490140.

The spelling of 16661631 in words is "sixteen million, six hundred sixty-one thousand, six hundred thirty-one".