55785991 has 2 divisors, whose sum is σ = 55785992. Its totient is φ = 55785990.

The previous prime is 55785979. The next prime is 55786013. The reversal of 55785991 is 19958755.

55785991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55785991 - 2⁹ = 55785479 is a prime.

It is a super-2 number, since 2×55785991² = 6224153583704162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55785901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27892995 + 27892996.

It is an arithmetic number, because the mean of its divisors is an integer number (27892996).

Almost surely, 2^55785991 is an apocalyptic number.

55785991 is a deficient number, since it is larger than the sum of its proper divisors (1).

55785991 is an equidigital number, since it uses as much as digits as its factorization.

55785991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 567000, while the sum is 49.

The square root of 55785991 is about 7469.0020083007. The cubic root of 55785991 is about 382.0982519124.

The spelling of 55785991 in words is "fifty-five million, seven hundred eighty-five thousand, nine hundred ninety-one".