1251255601 has 4 divisors (see below), whose sum is σ = 1251358704. Its totient is φ = 1251152500.

The previous prime is 1251255587. The next prime is 1251255647. The reversal of 1251255601 is 1065521521.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1065521521 = 5059 ⋅210619.

It is a cyclic number.

It is not a de Polignac number, because 1251255601 - 2¹³ = 1251247409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1251255601.

It is not an unprimeable number, because it can be changed into a prime (1251255101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30475 + ... + 58576.

It is an arithmetic number, because the mean of its divisors is an integer number (312839676).

Almost surely, 2^1251255601 is an apocalyptic number.

It is an amenable number.

1251255601 is a deficient number, since it is larger than the sum of its proper divisors (103103).

1251255601 is an equidigital number, since it uses as much as digits as its factorization.

1251255601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103102.

The product of its (nonzero) digits is 3000, while the sum is 28.

The square root of 1251255601 is about 35373.0914820856. The cubic root of 1251255601 is about 1077.5779056976.

The spelling of 1251255601 in words is "one billion, two hundred fifty-one million, two hundred fifty-five thousand, six hundred one".