16391749 has 6 divisors (see below), whose sum is σ = 18017510. Its totient is φ = 14901480.

The previous prime is 16391743. The next prime is 16391761. The reversal of 16391749 is 94719361.

It can be written as a sum of positive squares in only one way, i.e., 13176900 + 3214849 = 3630^2 + 1793^2 .

It is not a de Polignac number, because 16391749 - 2³ = 16391741 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 (16391741) by changing a digit.

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

It is an upside-down number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67614 + ... + 67855.

Almost surely, 2^16391749 is an apocalyptic number.

It is an amenable number.

16391749 is a deficient number, since it is larger than the sum of its proper divisors (1625761).

16391749 is a wasteful number, since it uses less digits than its factorization.

16391749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135491 (or 135480 counting only the distinct ones).

The product of its digits is 40824, while the sum is 40.

The square root of 16391749 is about 4048.6724984864. The cubic root of 16391749 is about 254.0242035753.

The spelling of 16391749 in words is "sixteen million, three hundred ninety-one thousand, seven hundred forty-nine".