19749 has 8 divisors (see below), whose sum is σ = 27360. Its totient is φ = 12656.

The previous prime is 19739. The next prime is 19751. The reversal of 19749 is 94791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19749 - 2⁵ = 19717 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a plaindrome in base 5.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 19749.

It is not an unprimeable number, because it can be changed into a prime (19709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27 + ... + 200.

It is an arithmetic number, because the mean of its divisors is an integer number (3420).

2¹⁹⁷⁴⁹ is an apocalyptic number.

It is an amenable number.

19749 is a deficient number, since it is larger than the sum of its proper divisors (7611).

19749 is a wasteful number, since it uses less digits than its factorization.

19749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259.

The product of its digits is 2268, while the sum is 30.

The square root of 19749 is about 140.5311353402. The cubic root of 19749 is about 27.0301446584.

It can be divided in two parts, 1974 and 9, that multiplied together give a triangular number (17766 = T₁₈₈).

The spelling of 19749 in words is "nineteen thousand, seven hundred forty-nine".