1217181061 has 4 divisors (see below), whose sum is σ = 1217261632. Its totient is φ = 1217100492.

The previous prime is 1217181047. The next prime is 1217181067. The reversal of 1217181061 is 1601817121.

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, and also a brilliant number, because the two primes have the same length.

It is a 3-Lehmer number, since φ(1217181061) divides (1217181061-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1217181061 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 (1217181067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10071 + ... + 50356.

It is an arithmetic number, because the mean of its divisors is an integer number (304315408).

It is a Poulet number, since it divides 2^1217181060-1.

Almost surely, 2^1217181061 is an apocalyptic number.

1217181061 is the 20143-rd octagonal number.

It is an amenable number.

1217181061 is a deficient number, since it is larger than the sum of its proper divisors (80571).

1217181061 is an equidigital number, since it uses as much as digits as its factorization.

1217181061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80570.

The product of its (nonzero) digits is 672, while the sum is 28.

The square root of 1217181061 is about 34888.1220618135. The cubic root of 1217181061 is about 1067.7061118286.

Adding to 1217181061 its reverse (1601817121), we get a palindrome (2818998182).

The spelling of 1217181061 in words is "one billion, two hundred seventeen million, one hundred eighty-one thousand, sixty-one".