1561536361 has 24 divisors (see below), whose sum is σ = 2002111776. Its totient is φ = 1204197120.

The previous prime is 1561536359. The next prime is 1561536391. The reversal of 1561536361 is 1636351651.

It is not a de Polignac number, because 1561536361 - 2¹ = 1561536359 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1561536361.

It is not an unprimeable number, because it can be changed into a prime (1561536391) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37350 + ... + 67216.

It is an arithmetic number, because the mean of its divisors is an integer number (83421324).

Almost surely, 2^1561536361 is an apocalyptic number.

1561536361 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1561536361 is a deficient number, since it is larger than the sum of its proper divisors (440575415).

1561536361 is a wasteful number, since it uses less digits than its factorization.

1561536361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29989 (or 29982 counting only the distinct ones).

The product of its digits is 48600, while the sum is 37.

The square root of 1561536361 is about 39516.2796958418. The cubic root of 1561536361 is about 1160.1586091583.

The spelling of 1561536361 in words is "one billion, five hundred sixty-one million, five hundred thirty-six thousand, three hundred sixty-one".