55139779 has 2 divisors, whose sum is σ = 55139780. Its totient is φ = 55139778.

The previous prime is 55139743. The next prime is 55139783. The reversal of 55139779 is 97793155.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55139779 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (55139719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27569889 + 27569890.

It is an arithmetic number, because the mean of its divisors is an integer number (27569890).

Almost surely, 2^55139779 is an apocalyptic number.

55139779 is a deficient number, since it is larger than the sum of its proper divisors (1).

55139779 is an equidigital number, since it uses as much as digits as its factorization.

55139779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 297675, while the sum is 46.

The square root of 55139779 is about 7425.6164053902. The cubic root of 55139779 is about 380.6171389290.

The spelling of 55139779 in words is "fifty-five million, one hundred thirty-nine thousand, seven hundred seventy-nine".