1213618661 has 8 divisors (see below), whose sum is σ = 1287005760. Its totient is φ = 1140453568.

The previous prime is 1213618643. The next prime is 1213618663. The reversal of 1213618661 is 1668163121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1213618661 - 2¹⁰ = 1213617637 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 (1213618663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44171 + ... + 66168.

It is an arithmetic number, because the mean of its divisors is an integer number (160875720).

Almost surely, 2^1213618661 is an apocalyptic number.

It is an amenable number.

1213618661 is a deficient number, since it is larger than the sum of its proper divisors (73387099).

1213618661 is a wasteful number, since it uses less digits than its factorization.

1213618661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111003.

The product of its digits is 10368, while the sum is 35.

The square root of 1213618661 is about 34837.0300255346. The cubic root of 1213618661 is about 1066.6634531913.

The spelling of 1213618661 in words is "one billion, two hundred thirteen million, six hundred eighteen thousand, six hundred sixty-one".