11551999999 has 4 divisors (see below), whose sum is σ = 11552417920. Its totient is φ = 11551582080.

The previous prime is 11551999997. The next prime is 11552000023. The reversal of 11551999999 is 99999915511.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99999915511 = 3037 ⋅32927203.

It is a cyclic number.

It is not a de Polignac number, because 11551999999 - 2¹ = 11551999997 is a prime.

It is a Duffinian number.

11551999999 is a modest number, since divided by 999999 gives 11551 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11551999997) 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, 164319 + ... + 223840.

It is an arithmetic number, because the mean of its divisors is an integer number (2888104480).

Almost surely, 2^11551999999 is an apocalyptic number.

11551999999 is a deficient number, since it is larger than the sum of its proper divisors (417921).

11551999999 is an equidigital number, since it uses as much as digits as its factorization.

11551999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417920.

The product of its digits is 13286025, while the sum is 67.

The spelling of 11551999999 in words is "eleven billion, five hundred fifty-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".