55561728381 has 16 divisors (see below), whose sum is σ = 74209935360. Its totient is φ = 36977396400.

The previous prime is 55561728377. The next prime is 55561728407. The reversal of 55561728381 is 18382716555.

It is not a de Polignac number, because 55561728381 - 2² = 55561728377 is a prime.

It is a super-2 number, since 2×55561728381² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55561728281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4456206 + ... + 4468656.

It is an arithmetic number, because the mean of its divisors is an integer number (4638120960).

Almost surely, 2^55561728381 is an apocalyptic number.

It is an amenable number.

55561728381 is a deficient number, since it is larger than the sum of its proper divisors (18648206979).

55561728381 is a wasteful number, since it uses less digits than its factorization.

55561728381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14896.

The product of its digits is 2016000, while the sum is 51.

The spelling of 55561728381 in words is "fifty-five billion, five hundred sixty-one million, seven hundred twenty-eight thousand, three hundred eighty-one".