1561141961 has 8 divisors (see below), whose sum is σ = 1597985664. Its totient is φ = 1524322800.

The previous prime is 1561141931. The next prime is 1561141991. The reversal of 1561141961 is 1691411651.

It is an interprime number because it is at equal distance from previous prime (1561141931) and next prime (1561141991).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561141961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561141931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 214736 + ... + 221886.

It is an arithmetic number, because the mean of its divisors is an integer number (199748208).

Almost surely, 2^1561141961 is an apocalyptic number.

It is an amenable number.

1561141961 is a deficient number, since it is larger than the sum of its proper divisors (36843703).

1561141961 is an equidigital number, since it uses as much as digits as its factorization.

1561141961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12271.

The product of its digits is 6480, while the sum is 35.

The square root of 1561141961 is about 39511.2890323766. The cubic root of 1561141961 is about 1160.0609264967.

The spelling of 1561141961 in words is "one billion, five hundred sixty-one million, one hundred forty-one thousand, nine hundred sixty-one".