981878749 has 2 divisors, whose sum is σ = 981878750. Its totient is φ = 981878748.

The previous prime is 981878747. The next prime is 981878797. The reversal of 981878749 is 947878189.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 536246649 + 445632100 = 23157^2 + 21110^2 .

It is a cyclic number.

It is not a de Polignac number, because 981878749 - 2¹ = 981878747 is a prime.

Together with 981878747, it forms a pair of twin primes.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (981878747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490939374 + 490939375.

It is an arithmetic number, because the mean of its divisors is an integer number (490939375).

Almost surely, 2^981878749 is an apocalyptic number.

It is an amenable number.

981878749 is a deficient number, since it is larger than the sum of its proper divisors (1).

981878749 is an equidigital number, since it uses as much as digits as its factorization.

981878749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8128512, while the sum is 61.

The square root of 981878749 is about 31334.9445348161. The cubic root of 981878749 is about 993.9227245409.

The spelling of 981878749 in words is "nine hundred eighty-one million, eight hundred seventy-eight thousand, seven hundred forty-nine".