1275115721 has 4 divisors (see below), whose sum is σ = 1391035344. Its totient is φ = 1159196100.

The previous prime is 1275115717. The next prime is 1275115741.

1275115721 is nontrivially palindromic in base 10.

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 1275115721 - 2² = 1275115717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1275115741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57959795 + ... + 57959816.

It is an arithmetic number, because the mean of its divisors is an integer number (347758836).

Almost surely, 2^1275115721 is an apocalyptic number.

1275115721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1275115721 is a deficient number, since it is larger than the sum of its proper divisors (115919623).

1275115721 is a wasteful number, since it uses less digits than its factorization.

1275115721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115919622.

The product of its digits is 4900, while the sum is 32.

The square root of 1275115721 is about 35708.7625240640. The cubic root of 1275115721 is about 1084.3842474453.

The spelling of 1275115721 in words is "one billion, two hundred seventy-five million, one hundred fifteen thousand, seven hundred twenty-one".