11551258721 has 4 divisors (see below), whose sum is σ = 11588401344. Its totient is φ = 11514116100.

The previous prime is 11551258699. The next prime is 11551258727. The reversal of 11551258721 is 12785215511.

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 a de Polignac number, because none of the positive numbers 2^k-11551258721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11551258727) 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, 18570845 + ... + 18571466.

It is an arithmetic number, because the mean of its divisors is an integer number (2897100336).

Almost surely, 2^11551258721 is an apocalyptic number.

It is an amenable number.

11551258721 is a deficient number, since it is larger than the sum of its proper divisors (37142623).

11551258721 is an equidigital number, since it uses as much as digits as its factorization.

11551258721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37142622.

The product of its digits is 28000, while the sum is 38.

The spelling of 11551258721 in words is "eleven billion, five hundred fifty-one million, two hundred fifty-eight thousand, seven hundred twenty-one".