1311020111 has 4 divisors (see below), whose sum is σ = 1321343232. Its totient is φ = 1300696992.

The previous prime is 1311020099. The next prime is 1311020147. The reversal of 1311020111 is 1110201131.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1110201131 = 13 ⋅85400087.

It is a cyclic number.

It is not a de Polignac number, because 1311020111 - 2⁶ = 1311020047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1311020092 and 1311020101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311028111) 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, 5161370 + ... + 5161623.

It is an arithmetic number, because the mean of its divisors is an integer number (330335808).

Almost surely, 2^1311020111 is an apocalyptic number.

1311020111 is a deficient number, since it is larger than the sum of its proper divisors (10323121).

1311020111 is a wasteful number, since it uses less digits than its factorization.

1311020111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10323120.

The product of its (nonzero) digits is 6, while the sum is 11.

The square root of 1311020111 is about 36208.0116963083. The cubic root of 1311020111 is about 1094.4681253114.

Adding to 1311020111 its reverse (1110201131), we get a palindrome (2421221242).

It can be divided in two parts, 1311020 and 111, that added together give a palindrome (1311131).

The spelling of 1311020111 in words is "one billion, three hundred eleven million, twenty thousand, one hundred eleven".