1561142123 has 4 divisors (see below), whose sum is σ = 1614974640. Its totient is φ = 1507309608.

The previous prime is 1561142101. The next prime is 1561142159. The reversal of 1561142123 is 3212411651.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1561142123 - 2⁸ = 1561141867 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1561142092 and 1561142101.

It is not an unprimeable number, because it can be changed into a prime (1561147123) 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, 26916215 + ... + 26916272.

It is an arithmetic number, because the mean of its divisors is an integer number (403743660).

Almost surely, 2^1561142123 is an apocalyptic number.

1561142123 is a deficient number, since it is larger than the sum of its proper divisors (53832517).

1561142123 is an equidigital number, since it uses as much as digits as its factorization.

1561142123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53832516.

The product of its digits is 1440, while the sum is 26.

The square root of 1561142123 is about 39511.2910824235. The cubic root of 1561142123 is about 1160.0609666233.

Adding to 1561142123 its reverse (3212411651), we get a palindrome (4773553774).

The spelling of 1561142123 in words is "one billion, five hundred sixty-one million, one hundred forty-two thousand, one hundred twenty-three".