55561810861 has 4 divisors (see below), whose sum is σ = 57977541792. Its totient is φ = 53146079932.

The previous prime is 55561810859. The next prime is 55561810867. The reversal of 55561810861 is 16801816555.

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 55561810861 - 2¹ = 55561810859 is a prime.

It is a super-2 number, since 2×55561810861² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55561810867) 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, 1207865431 + ... + 1207865476.

It is an arithmetic number, because the mean of its divisors is an integer number (14494385448).

Almost surely, 2^55561810861 is an apocalyptic number.

It is an amenable number.

55561810861 is a deficient number, since it is larger than the sum of its proper divisors (2415730931).

55561810861 is a wasteful number, since it uses less digits than its factorization.

55561810861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2415730930.

The product of its (nonzero) digits is 288000, while the sum is 46.

The spelling of 55561810861 in words is "fifty-five billion, five hundred sixty-one million, eight hundred ten thousand, eight hundred sixty-one".