1561010161 has 4 divisors (see below), whose sum is σ = 1628880192. Its totient is φ = 1493140132.

The previous prime is 1561010147. The next prime is 1561010167. The reversal of 1561010161 is 1610101651.

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.

It is a cyclic number.

It is not a de Polignac number, because 1561010161 - 2¹⁹ = 1560485873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561010167) 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, 33934981 + ... + 33935026.

It is an arithmetic number, because the mean of its divisors is an integer number (407220048).

Almost surely, 2^1561010161 is an apocalyptic number.

It is an amenable number.

1561010161 is a deficient number, since it is larger than the sum of its proper divisors (67870031).

1561010161 is an equidigital number, since it uses as much as digits as its factorization.

1561010161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67870030.

The product of its (nonzero) digits is 180, while the sum is 22.

The square root of 1561010161 is about 39509.6211194185. The cubic root of 1561010161 is about 1160.0282793839.

The spelling of 1561010161 in words is "one billion, five hundred sixty-one million, ten thousand, one hundred sixty-one".