1561516403 has 2 divisors, whose sum is σ = 1561516404. Its totient is φ = 1561516402.

The previous prime is 1561516399. The next prime is 1561516423. The reversal of 1561516403 is 3046151651.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1561516403 - 2² = 1561516399 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1561516403.

It is not a weakly prime, because it can be changed into another prime (1561516423) 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, 780758201 + 780758202.

It is an arithmetic number, because the mean of its divisors is an integer number (780758202).

Almost surely, 2^1561516403 is an apocalyptic number.

1561516403 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561516403 is an equidigital number, since it uses as much as digits as its factorization.

1561516403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 1561516403 is about 39516.0271662018. The cubic root of 1561516403 is about 1160.1536664739.

The spelling of 1561516403 in words is "one billion, five hundred sixty-one million, five hundred sixteen thousand, four hundred three".