18071649 has 6 divisors (see below), whose sum is σ = 26103506. Its totient is φ = 12047760.

The previous prime is 18071639. The next prime is 18071671. The reversal of 18071649 is 94617081.

18071649 is a `hidden beast` number, since 1 + 8 + 0 + 7 + 1 + 649 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 431649 = 4200^2 + 657^2 .

It is not a de Polignac number, because 18071649 - 2⁴ = 18071633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18071609) 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, 1003972 + ... + 1003989.

Almost surely, 2^18071649 is an apocalyptic number.

It is an amenable number.

18071649 is a deficient number, since it is larger than the sum of its proper divisors (8031857).

18071649 is a wasteful number, since it uses less digits than its factorization.

18071649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2007967 (or 2007964 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 18071649 is about 4251.0762166774. The cubic root of 18071649 is about 262.4214077644.

The spelling of 18071649 in words is "eighteen million, seventy-one thousand, six hundred forty-nine".