1216617761 has 2 divisors, whose sum is σ = 1216617762. Its totient is φ = 1216617760.

The previous prime is 1216617751. The next prime is 1216617793. The reversal of 1216617761 is 1677166121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1214940736 + 1677025 = 34856^2 + 1295^2 .

It is an emirp because it is prime and its reverse (1677166121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1216617761 - 2¹⁴ = 1216601377 is a prime.

It is not a weakly prime, because it can be changed into another prime (1216617751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608308880 + 608308881.

It is an arithmetic number, because the mean of its divisors is an integer number (608308881).

Almost surely, 2^1216617761 is an apocalyptic number.

It is an amenable number.

1216617761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216617761 is an equidigital number, since it uses as much as digits as its factorization.

1216617761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 38.

The square root of 1216617761 is about 34880.0481794392. The cubic root of 1216617761 is about 1067.5413782826.

The spelling of 1216617761 in words is "one billion, two hundred sixteen million, six hundred seventeen thousand, seven hundred sixty-one".