1361777620661 has 2 divisors, whose sum is σ = 1361777620662. Its totient is φ = 1361777620660.

The previous prime is 1361777620649. The next prime is 1361777620729. The reversal of 1361777620661 is 1660267771631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1214172591025 + 147605029636 = 1101895^2 + 384194^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1361777620661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1361777628661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 680888810330 + 680888810331.

It is an arithmetic number, because the mean of its divisors is an integer number (680888810331).

Almost surely, 2^{1361777620661} is an apocalyptic number.

It is an amenable number.

1361777620661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1361777620661 is an equidigital number, since it uses as much as digits as its factorization.

1361777620661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2667168, while the sum is 53.

The spelling of 1361777620661 in words is "one trillion, three hundred sixty-one billion, seven hundred seventy-seven million, six hundred twenty thousand, six hundred sixty-one".