391968749 has 2 divisors, whose sum is σ = 391968750. Its totient is φ = 391968748.

The previous prime is 391968719. The next prime is 391968757. The reversal of 391968749 is 947869193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 360810025 + 31158724 = 18995^2 + 5582^2 .

It is an emirp because it is prime and its reverse (947869193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391968749 - 2¹² = 391964653 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 391968694 and 391968703.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391968719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195984374 + 195984375.

It is an arithmetic number, because the mean of its divisors is an integer number (195984375).

Almost surely, 2^391968749 is an apocalyptic number.

It is an amenable number.

391968749 is a deficient number, since it is larger than the sum of its proper divisors (1).

391968749 is an equidigital number, since it uses as much as digits as its factorization.

391968749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2939328, while the sum is 56.

The square root of 391968749 is about 19798.2006505642. The cubic root of 391968749 is about 731.8416930247.

The spelling of 391968749 in words is "three hundred ninety-one million, nine hundred sixty-eight thousand, seven hundred forty-nine".