1561430663 has 32 divisors (see below), whose sum is σ = 1777391616. Its totient is φ = 1362106368.

The previous prime is 1561430639. The next prime is 1561430669. The reversal of 1561430663 is 3660341651.

It is a cyclic number.

It is not a de Polignac number, because 1561430663 - 2²⁴ = 1544653447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561430669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2705831 + ... + 2706407.

It is an arithmetic number, because the mean of its divisors is an integer number (55543488).

Almost surely, 2^1561430663 is an apocalyptic number.

1561430663 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1561430663 is a deficient number, since it is larger than the sum of its proper divisors (215960953).

1561430663 is a wasteful number, since it uses less digits than its factorization.

1561430663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783.

The product of its (nonzero) digits is 38880, while the sum is 35.

The square root of 1561430663 is about 39514.9422750432. The cubic root of 1561430663 is about 1160.1324321157.

The spelling of 1561430663 in words is "one billion, five hundred sixty-one million, four hundred thirty thousand, six hundred sixty-three".