16531691 has 16 divisors (see below), whose sum is σ = 19232640. Its totient is φ = 14051520.

The previous prime is 16531679. The next prime is 16531709. The reversal of 16531691 is 19613561.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 16531691 - 2²² = 12337387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16531621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16871 + ... + 17823.

It is an arithmetic number, because the mean of its divisors is an integer number (1202040).

Almost surely, 2^16531691 is an apocalyptic number.

16531691 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

16531691 is a deficient number, since it is larger than the sum of its proper divisors (2700949).

16531691 is a wasteful number, since it uses less digits than its factorization.

16531691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066.

The product of its digits is 4860, while the sum is 32.

The square root of 16531691 is about 4065.9182234767. The cubic root of 16531691 is about 254.7450534065.

The spelling of 16531691 in words is "sixteen million, five hundred thirty-one thousand, six hundred ninety-one".