19869749 has 2 divisors, whose sum is σ = 19869750. Its totient is φ = 19869748.

The previous prime is 19869709. The next prime is 19869757. The reversal of 19869749 is 94796891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19864849 + 4900 = 4457^2 + 70^2 .

It is a cyclic number.

It is not a de Polignac number, because 19869749 - 2¹² = 19865653 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 19869749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19869709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9934874 + 9934875.

It is an arithmetic number, because the mean of its divisors is an integer number (9934875).

Almost surely, 2^19869749 is an apocalyptic number.

It is an amenable number.

19869749 is a deficient number, since it is larger than the sum of its proper divisors (1).

19869749 is an equidigital number, since it uses as much as digits as its factorization.

19869749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 53.

The square root of 19869749 is about 4457.5496632118. The cubic root of 19869749 is about 270.8512184691.

The spelling of 19869749 in words is "nineteen million, eight hundred sixty-nine thousand, seven hundred forty-nine".