1236642452561 has 2 divisors, whose sum is σ = 1236642452562. Its totient is φ = 1236642452560.

The previous prime is 1236642452557. The next prime is 1236642452581. The reversal of 1236642452561 is 1652542466321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1165223097025 + 71419355536 = 1079455^2 + 267244^2 .

It is a cyclic number.

It is not a de Polignac number, because 1236642452561 - 2² = 1236642452557 is a prime.

It is not a weakly prime, because it can be changed into another prime (1236642452581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 618321226280 + 618321226281.

It is an arithmetic number, because the mean of its divisors is an integer number (618321226281).

Almost surely, 2^{1236642452561} is an apocalyptic number.

It is an amenable number.

1236642452561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1236642452561 is an equidigital number, since it uses as much as digits as its factorization.

1236642452561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2073600, while the sum is 47.

The spelling of 1236642452561 in words is "one trillion, two hundred thirty-six billion, six hundred forty-two million, four hundred fifty-two thousand, five hundred sixty-one".