1561226801 has 2 divisors, whose sum is σ = 1561226802. Its totient is φ = 1561226800.

The previous prime is 1561226761. The next prime is 1561226819. The reversal of 1561226801 is 1086221651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1320232225 + 240994576 = 36335^2 + 15524^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561226801 is a prime.

It is not a weakly prime, because it can be changed into another prime (1561226851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780613400 + 780613401.

It is an arithmetic number, because the mean of its divisors is an integer number (780613401).

Almost surely, 2^1561226801 is an apocalyptic number.

It is an amenable number.

1561226801 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561226801 is an equidigital number, since it uses as much as digits as its factorization.

1561226801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 1561226801 is about 39512.3626350032. The cubic root of 1561226801 is about 1160.0819405554.

The spelling of 1561226801 in words is "one billion, five hundred sixty-one million, two hundred twenty-six thousand, eight hundred one".