1638749 has 16 divisors (see below), whose sum is σ = 2032128. Its totient is φ = 1289472.

The previous prime is 1638743. The next prime is 1638797. The reversal of 1638749 is 9478361.

It is a cyclic number.

It is not a de Polignac number, because 1638749 - 2⁴ = 1638733 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638743) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5447 + ... + 5739.

It is an arithmetic number, because the mean of its divisors is an integer number (127008).

2^1638749 is an apocalyptic number.

It is an amenable number.

1638749 is a deficient number, since it is larger than the sum of its proper divisors (393379).

1638749 is a wasteful number, since it uses less digits than its factorization.

1638749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364.

The product of its digits is 36288, while the sum is 38.

The square root of 1638749 is about 1280.1363208659. The cubic root of 1638749 is about 117.8973779807.

The spelling of 1638749 in words is "one million, six hundred thirty-eight thousand, seven hundred forty-nine".