1256265665 has 8 divisors (see below), whose sum is σ = 1510162368. Its totient is φ = 1003250160.

The previous prime is 1256265641. The next prime is 1256265691. The reversal of 1256265665 is 5665626521.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-1256265665 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 217157 + ... + 222866.

It is an arithmetic number, because the mean of its divisors is an integer number (188770296).

Almost surely, 2^1256265665 is an apocalyptic number.

It is an amenable number.

1256265665 is a deficient number, since it is larger than the sum of its proper divisors (253896703).

1256265665 is an equidigital number, since it uses as much as digits as its factorization.

1256265665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440599.

The product of its digits is 648000, while the sum is 44.

The square root of 1256265665 is about 35443.8381809871. The cubic root of 1256265665 is about 1079.0142082113.

The spelling of 1256265665 in words is "one billion, two hundred fifty-six million, two hundred sixty-five thousand, six hundred sixty-five".