55181999 has 2 divisors, whose sum is σ = 55182000. Its totient is φ = 55181998.

The previous prime is 55181939. The next prime is 55182007. The reversal of 55181999 is 99918155.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55181999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55181939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27590999 + 27591000.

It is an arithmetic number, because the mean of its divisors is an integer number (27591000).

Almost surely, 2^55181999 is an apocalyptic number.

55181999 is a deficient number, since it is larger than the sum of its proper divisors (1).

55181999 is an equidigital number, since it uses as much as digits as its factorization.

55181999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145800, while the sum is 47.

The square root of 55181999 is about 7428.4587230461. The cubic root of 55181999 is about 380.7142591096.

The spelling of 55181999 in words is "fifty-five million, one hundred eighty-one thousand, nine hundred ninety-nine".