1101115661 has 4 divisors (see below), whose sum is σ = 1101963324. Its totient is φ = 1100268000.

The previous prime is 1101115649. The next prime is 1101115747. The reversal of 1101115661 is 1665111011.

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: 1665111011 = 1451 ⋅1147561.

It can be written as a sum of positive squares in 2 ways, for example, as 866761 + 1100248900 = 931^2 + 33170^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1101115661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1101115601) 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, 421880 + ... + 424481.

It is an arithmetic number, because the mean of its divisors is an integer number (275490831).

Almost surely, 2^1101115661 is an apocalyptic number.

It is an amenable number.

1101115661 is a deficient number, since it is larger than the sum of its proper divisors (847663).

1101115661 is an equidigital number, since it uses as much as digits as its factorization.

1101115661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 847662.

The product of its (nonzero) digits is 180, while the sum is 23.

The square root of 1101115661 is about 33183.0628634549. The cubic root of 1101115661 is about 1032.6289898588.

Adding to 1101115661 its reverse (1665111011), we get a palindrome (2766226672).

The spelling of 1101115661 in words is "one billion, one hundred one million, one hundred fifteen thousand, six hundred sixty-one".