55478509 has 2 divisors, whose sum is σ = 55478510. Its totient is φ = 55478508.

The previous prime is 55478419. The next prime is 55478513. The reversal of 55478509 is 90587455.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 48692484 + 6786025 = 6978^2 + 2605^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55478509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55478519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27739254 + 27739255.

It is an arithmetic number, because the mean of its divisors is an integer number (27739255).

Almost surely, 2^55478509 is an apocalyptic number.

It is an amenable number.

55478509 is a deficient number, since it is larger than the sum of its proper divisors (1).

55478509 is an equidigital number, since it uses as much as digits as its factorization.

55478509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252000, while the sum is 43.

The square root of 55478509 is about 7448.3896917387. The cubic root of 55478509 is about 381.3949399999.

The spelling of 55478509 in words is "fifty-five million, four hundred seventy-eight thousand, five hundred nine".