1265855001 has 4 divisors (see below), whose sum is σ = 1687806672. Its totient is φ = 843903332.

The previous prime is 1265854973. The next prime is 1265855011. The reversal of 1265855001 is 1005585621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1265855001 - 2⁶ = 1265854937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1265855011) 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, 210975831 + ... + 210975836.

It is an arithmetic number, because the mean of its divisors is an integer number (421951668).

Almost surely, 2^1265855001 is an apocalyptic number.

It is an amenable number.

1265855001 is a deficient number, since it is larger than the sum of its proper divisors (421951671).

1265855001 is an equidigital number, since it uses as much as digits as its factorization.

1265855001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421951670.

The product of its (nonzero) digits is 12000, while the sum is 33.

The square root of 1265855001 is about 35578.8560945964. The cubic root of 1265855001 is about 1081.7526984715.

The spelling of 1265855001 in words is "one billion, two hundred sixty-five million, eight hundred fifty-five thousand, one".