1213663761 has 12 divisors (see below), whose sum is σ = 1757957760. Its totient is φ = 806853240.

The previous prime is 1213663753. The next prime is 1213663799. The reversal of 1213663761 is 1673663121.

1213663761 is a `hidden beast` number, since 1 + 2 + 13 + 6 + 637 + 6 + 1 = 666.

It is not a de Polignac number, because 1213663761 - 2³ = 1213663753 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1213663861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184585 + ... + 191046.

It is an arithmetic number, because the mean of its divisors is an integer number (146496480).

Almost surely, 2^1213663761 is an apocalyptic number.

It is an amenable number.

1213663761 is a deficient number, since it is larger than the sum of its proper divisors (544293999).

1213663761 is a wasteful number, since it uses less digits than its factorization.

1213663761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375996 (or 375993 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 1213663761 is about 34837.6773192473. The cubic root of 1213663761 is about 1066.6766659978.

The spelling of 1213663761 in words is "one billion, two hundred thirteen million, six hundred sixty-three thousand, seven hundred sixty-one".