11551211881 has 12 divisors (see below), whose sum is σ = 12699986992. Its totient is φ = 10498455000.

The previous prime is 11551211873. The next prime is 11551211933. The reversal of 11551211881 is 18811215511.

It is a happy number.

It is not a de Polignac number, because 11551211881 - 2³ = 11551211873 is a prime.

It is a super-2 number, since 2×11551211881² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (11551211831) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 596806 + ... + 615856.

Almost surely, 2^11551211881 is an apocalyptic number.

11551211881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11551211881 is a deficient number, since it is larger than the sum of its proper divisors (1148775111).

11551211881 is a wasteful number, since it uses less digits than its factorization.

11551211881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24084 (or 24073 counting only the distinct ones).

The product of its digits is 3200, while the sum is 34.

The spelling of 11551211881 in words is "eleven billion, five hundred fifty-one million, two hundred eleven thousand, eight hundred eighty-one".