249665257 has 4 divisors (see below), whose sum is σ = 250307460. Its totient is φ = 249023056.

The previous prime is 249665239. The next prime is 249665261. The reversal of 249665257 is 752566942.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 752566942 = 2 ⋅376283471.

It can be written as a sum of positive squares in 2 ways, for example, as 43771456 + 205893801 = 6616^2 + 14349^2 .

It is a cyclic number.

It is not a de Polignac number, because 249665257 - 2¹¹ = 249663209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (249665357) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 320518 + ... + 321295.

It is an arithmetic number, because the mean of its divisors is an integer number (62576865).

Almost surely, 2^249665257 is an apocalyptic number.

It is an amenable number.

249665257 is a deficient number, since it is larger than the sum of its proper divisors (642203).

249665257 is an equidigital number, since it uses as much as digits as its factorization.

249665257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642202.

The product of its digits is 907200, while the sum is 46.

The square root of 249665257 is about 15800.7992519366. The cubic root of 249665257 is about 629.6792328613.

The spelling of 249665257 in words is "two hundred forty-nine million, six hundred sixty-five thousand, two hundred fifty-seven".