20199749 has 4 divisors (see below), whose sum is σ = 20211360. Its totient is φ = 20188140.

The previous prime is 20199737. The next prime is 20199769. The reversal of 20199749 is 94799102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 94799102 = 2 ⋅47399551.

It is a cyclic number.

It is not a de Polignac number, because 20199749 - 2⁸ = 20199493 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 (20199709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2609 + ... + 6870.

It is an arithmetic number, because the mean of its divisors is an integer number (5052840).

Almost surely, 2^20199749 is an apocalyptic number.

It is an amenable number.

20199749 is a deficient number, since it is larger than the sum of its proper divisors (11611).

20199749 is an equidigital number, since it uses as much as digits as its factorization.

20199749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11610.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 20199749 is about 4494.4130873786. The cubic root of 20199749 is about 272.3424401285.

The spelling of 20199749 in words is "twenty million, one hundred ninety-nine thousand, seven hundred forty-nine".