55681331 has 2 divisors, whose sum is σ = 55681332. Its totient is φ = 55681330.

The previous prime is 55681319. The next prime is 55681357. The reversal of 55681331 is 13318655.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55681331 - 2¹⁸ = 55419187 is a prime.

It is a super-2 number, since 2×55681331² = 6200821243863122, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (55681361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27840665 + 27840666.

It is an arithmetic number, because the mean of its divisors is an integer number (27840666).

Almost surely, 2^55681331 is an apocalyptic number.

55681331 is a deficient number, since it is larger than the sum of its proper divisors (1).

55681331 is an equidigital number, since it uses as much as digits as its factorization.

55681331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10800, while the sum is 32.

The square root of 55681331 is about 7461.9924282996. The cubic root of 55681331 is about 381.8591510374.

Adding to 55681331 its reverse (13318655), we get a palindrome (68999986).

The spelling of 55681331 in words is "fifty-five million, six hundred eighty-one thousand, three hundred thirty-one".