249775661 has 2 divisors, whose sum is σ = 249775662. Its totient is φ = 249775660.

The previous prime is 249775651. The next prime is 249775693. The reversal of 249775661 is 166577942.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190578025 + 59197636 = 13805^2 + 7694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-249775661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (249775601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124887830 + 124887831.

It is an arithmetic number, because the mean of its divisors is an integer number (124887831).

Almost surely, 2^249775661 is an apocalyptic number.

It is an amenable number.

249775661 is a deficient number, since it is larger than the sum of its proper divisors (1).

249775661 is an equidigital number, since it uses as much as digits as its factorization.

249775661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 47.

The square root of 249775661 is about 15804.2924865367. The cubic root of 249775661 is about 629.7720356032.

The spelling of 249775661 in words is "two hundred forty-nine million, seven hundred seventy-five thousand, six hundred sixty-one".