1561145983 has 2 divisors, whose sum is σ = 1561145984. Its totient is φ = 1561145982.

The previous prime is 1561145981. The next prime is 1561146017. The reversal of 1561145983 is 3895411651.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1561145983 - 2¹ = 1561145981 is a prime.

Together with 1561145981, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561145981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780572991 + 780572992.

It is an arithmetic number, because the mean of its divisors is an integer number (780572992).

Almost surely, 2^1561145983 is an apocalyptic number.

1561145983 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561145983 is an equidigital number, since it uses as much as digits as its factorization.

1561145983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 43.

The square root of 1561145983 is about 39511.3399291899. The cubic root of 1561145983 is about 1160.0619227249.

The spelling of 1561145983 in words is "one billion, five hundred sixty-one million, one hundred forty-five thousand, nine hundred eighty-three".