1561501099 has 2 divisors, whose sum is σ = 1561501100. Its totient is φ = 1561501098.

The previous prime is 1561501087. The next prime is 1561501133. The reversal of 1561501099 is 9901051651.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1561501099 - 2⁷ = 1561500971 is a prime.

It is not a weakly prime, because it can be changed into another prime (1561501199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780750549 + 780750550.

It is an arithmetic number, because the mean of its divisors is an integer number (780750550).

Almost surely, 2^1561501099 is an apocalyptic number.

1561501099 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561501099 is an equidigital number, since it uses as much as digits as its factorization.

1561501099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12150, while the sum is 37.

The square root of 1561501099 is about 39515.8335227792. The cubic root of 1561501099 is about 1160.1498763441.

The spelling of 1561501099 in words is "one billion, five hundred sixty-one million, five hundred one thousand, ninety-nine".