55399661 has 2 divisors, whose sum is σ = 55399662. Its totient is φ = 55399660.

The previous prime is 55399639. The next prime is 55399679. The reversal of 55399661 is 16699355.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49970761 + 5428900 = 7069^2 + 2330^2 .

It is a cyclic number.

It is not a de Polignac number, because 55399661 - 2¹⁴ = 55383277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55399601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27699830 + 27699831.

It is an arithmetic number, because the mean of its divisors is an integer number (27699831).

Almost surely, 2^55399661 is an apocalyptic number.

It is an amenable number.

55399661 is a deficient number, since it is larger than the sum of its proper divisors (1).

55399661 is an equidigital number, since it uses as much as digits as its factorization.

55399661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 218700, while the sum is 44.

The square root of 55399661 is about 7443.0948536210. The cubic root of 55399661 is about 381.2141703854.

The spelling of 55399661 in words is "fifty-five million, three hundred ninety-nine thousand, six hundred sixty-one".