1216841978797 has 2 divisors, whose sum is σ = 1216841978798. Its totient is φ = 1216841978796.

The previous prime is 1216841978731. The next prime is 1216841978917. The reversal of 1216841978797 is 7978791486121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 912065110441 + 304776868356 = 955021^2 + 552066^2 .

It is an emirp because it is prime and its reverse (7978791486121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1216841978797 - 2¹⁵ = 1216841946029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216841978717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608420989398 + 608420989399.

It is an arithmetic number, because the mean of its divisors is an integer number (608420989399).

Almost surely, 2^{1216841978797} is an apocalyptic number.

It is an amenable number.

1216841978797 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216841978797 is an equidigital number, since it uses as much as digits as its factorization.

1216841978797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 85349376, while the sum is 70.

The spelling of 1216841978797 in words is "one trillion, two hundred sixteen billion, eight hundred forty-one million, nine hundred seventy-eight thousand, seven hundred ninety-seven".