1561801147 has 2 divisors, whose sum is σ = 1561801148. Its totient is φ = 1561801146.

The previous prime is 1561801141. The next prime is 1561801181. The reversal of 1561801147 is 7411081651.

It is an a-pointer prime, because the next prime (1561801181) can be obtained adding 1561801147 to its sum of digits (34).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561801147 is a prime.

It is not a weakly prime, because it can be changed into another prime (1561801141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780900573 + 780900574.

It is an arithmetic number, because the mean of its divisors is an integer number (780900574).

Almost surely, 2^1561801147 is an apocalyptic number.

1561801147 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561801147 is an equidigital number, since it uses as much as digits as its factorization.

1561801147 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 34.

The square root of 1561801147 is about 39519.6298945220. The cubic root of 1561801147 is about 1160.2241805625.

Adding to 1561801147 its reverse (7411081651), we get a palindrome (8972882798).

The spelling of 1561801147 in words is "one billion, five hundred sixty-one million, eight hundred one thousand, one hundred forty-seven".