1561065101 has 4 divisors (see below), whose sum is σ = 1561166400. Its totient is φ = 1560963804.

The previous prime is 1561065083. The next prime is 1561065139. The reversal of 1561065101 is 1015601651.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561065101 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 (1561065301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22211 + ... + 60128.

It is an arithmetic number, because the mean of its divisors is an integer number (390291600).

Almost surely, 2^1561065101 is an apocalyptic number.

It is an amenable number.

1561065101 is a deficient number, since it is larger than the sum of its proper divisors (101299).

1561065101 is an equidigital number, since it uses as much as digits as its factorization.

1561065101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101298.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 1561065101 is about 39510.3163869894. The cubic root of 1561065101 is about 1160.0418883506.

Adding to 1561065101 its reverse (1015601651), we get a palindrome (2576666752).

The spelling of 1561065101 in words is "one billion, five hundred sixty-one million, sixty-five thousand, one hundred one".