7855855561 has 4 divisors (see below), whose sum is σ = 8023001472. Its totient is φ = 7688709652.

The previous prime is 7855855549. The next prime is 7855855571. The reversal of 7855855561 is 1655585587.

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 7855855561 - 2²⁵ = 7822301129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7855855541) 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, 83572885 + ... + 83572978.

It is an arithmetic number, because the mean of its divisors is an integer number (2005750368).

Almost surely, 2^7855855561 is an apocalyptic number.

It is an amenable number.

7855855561 is a deficient number, since it is larger than the sum of its proper divisors (167145911).

7855855561 is a wasteful number, since it uses less digits than its factorization.

7855855561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167145910.

The product of its digits is 8400000, while the sum is 55.

The square root of 7855855561 is about 88633.2644157937. The cubic root of 7855855561 is about 1987.9150879455.

The spelling of 7855855561 in words is "seven billion, eight hundred fifty-five million, eight hundred fifty-five thousand, five hundred sixty-one".