1561490866663 has 54 divisors (see below), whose sum is σ = 1976941491144. Its totient is φ = 1207614537792.

The previous prime is 1561490866643. The next prime is 1561490866673. The reversal of 1561490866663 is 3666680941651.

It is a de Polignac number, because none of the positive numbers 2^k-1561490866663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561490866643) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 2020039545 + ... + 2020040317.

Almost surely, 2^{1561490866663} is an apocalyptic number.

1561490866663 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1561490866663 is a deficient number, since it is larger than the sum of its proper divisors (415450624481).

1561490866663 is an frugal number, since it uses more digits than its factorization.

1561490866663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1673 (or 840 counting only the distinct ones).

The product of its (nonzero) digits is 33592320, while the sum is 61.

The spelling of 1561490866663 in words is "one trillion, five hundred sixty-one billion, four hundred ninety million, eight hundred sixty-six thousand, six hundred sixty-three".