249039761561 has 2 divisors, whose sum is σ = 249039761562. Its totient is φ = 249039761560.

The previous prime is 249039761497. The next prime is 249039761567. The reversal of 249039761561 is 165167930942.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 219056761225 + 29983000336 = 468035^2 + 173156^2 .

It is a cyclic number.

It is not a de Polignac number, because 249039761561 - 2⁶ = 249039761497 is a prime.

It is not a weakly prime, because it can be changed into another prime (249039761567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124519880780 + 124519880781.

It is an arithmetic number, because the mean of its divisors is an integer number (124519880781).

Almost surely, 2^249039761561 is an apocalyptic number.

It is an amenable number.

249039761561 is a deficient number, since it is larger than the sum of its proper divisors (1).

249039761561 is an equidigital number, since it uses as much as digits as its factorization.

249039761561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2449440, while the sum is 53.

The spelling of 249039761561 in words is "two hundred forty-nine billion, thirty-nine million, seven hundred sixty-one thousand, five hundred sixty-one".