249778681 has 2 divisors, whose sum is σ = 249778682. Its totient is φ = 249778680.

The previous prime is 249778663. The next prime is 249778699. The reversal of 249778681 is 186877942.

It is a balanced prime because it is at equal distance from previous prime (249778663) and next prime (249778699).

It can be written as a sum of positive squares in only one way, i.e., 228765625 + 21013056 = 15125^2 + 4584^2 .

It is a cyclic number.

It is not a de Polignac number, because 249778681 - 2¹⁵ = 249745913 is a prime.

It is a super-2 number, since 2×249778681² = 124778778964199522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (249778181) 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, 124889340 + 124889341.

It is an arithmetic number, because the mean of its divisors is an integer number (124889341).

Almost surely, 2^249778681 is an apocalyptic number.

It is an amenable number.

249778681 is a deficient number, since it is larger than the sum of its proper divisors (1).

249778681 is an equidigital number, since it uses as much as digits as its factorization.

249778681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1354752, while the sum is 52.

The square root of 249778681 is about 15804.3880299112. The cubic root of 249778681 is about 629.7745737527.

The spelling of 249778681 in words is "two hundred forty-nine million, seven hundred seventy-eight thousand, six hundred eighty-one".