8261561861 has 8 divisors (see below), whose sum is σ = 9451058880. Its totient is φ = 7074383328.

The previous prime is 8261561849. The next prime is 8261561863. The reversal of 8261561861 is 1681651628.

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

It is a cyclic number.

It is not a de Polignac number, because 8261561861 - 2¹⁰ = 8261560837 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 (8261561863) 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, 571976 + ... + 586241.

It is an arithmetic number, because the mean of its divisors is an integer number (1181382360).

Almost surely, 2^8261561861 is an apocalyptic number.

It is an amenable number.

8261561861 is a deficient number, since it is larger than the sum of its proper divisors (1189497019).

8261561861 is a wasteful number, since it uses less digits than its factorization.

8261561861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1159243.

The product of its digits is 138240, while the sum is 44.

The square root of 8261561861 is about 90893.1342896701. The cubic root of 8261561861 is about 2021.5634940549.

The spelling of 8261561861 in words is "eight billion, two hundred sixty-one million, five hundred sixty-one thousand, eight hundred sixty-one".