55555681 has 2 divisors, whose sum is σ = 55555682. Its totient is φ = 55555680.

The previous prime is 55555679. The next prime is 55555727. The reversal of 55555681 is 18655555.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50339025 + 5216656 = 7095^2 + 2284^2 .

It is a cyclic number.

It is not a de Polignac number, because 55555681 - 2¹ = 55555679 is a prime.

It is a super-2 number, since 2×55555681² = 6172867382747522, which contains 22 as substring.

Together with 55555679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (55555631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27777840 + 27777841.

It is an arithmetic number, because the mean of its divisors is an integer number (27777841).

Almost surely, 2^55555681 is an apocalyptic number.

It is an amenable number.

55555681 is a deficient number, since it is larger than the sum of its proper divisors (1).

55555681 is an equidigital number, since it uses as much as digits as its factorization.

55555681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150000, while the sum is 40.

The square root of 55555681 is about 7453.5683400637. The cubic root of 55555681 is about 381.5717013803.

It can be divided in two parts, 5555 and 5681, that added together give a square (11236 = 106²).

The spelling of 55555681 in words is "fifty-five million, five hundred fifty-five thousand, six hundred eighty-one".