1217120661 has 48 divisors (see below), whose sum is σ = 1982844864. Its totient is φ = 742950144.

The previous prime is 1217120659. The next prime is 1217120687. The reversal of 1217120661 is 1660217121.

It is a happy number.

It is not a de Polignac number, because 1217120661 - 2¹ = 1217120659 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217120621) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 148866 + ... + 156828.

It is an arithmetic number, because the mean of its divisors is an integer number (41309268).

Almost surely, 2^1217120661 is an apocalyptic number.

It is an amenable number.

1217120661 is a deficient number, since it is larger than the sum of its proper divisors (765724203).

1217120661 is an equidigital number, since it uses as much as digits as its factorization.

1217120661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8032 (or 8020 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 1217120661 is about 34887.2564269534. The cubic root of 1217120661 is about 1067.6884506610.

Adding to 1217120661 its reverse (1660217121), we get a palindrome (2877337782).

The spelling of 1217120661 in words is "one billion, two hundred seventeen million, one hundred twenty thousand, six hundred sixty-one".