55555531999909 has 2 divisors, whose sum is σ = 55555531999910. Its totient is φ = 55555531999908.

The previous prime is 55555531999907. The next prime is 55555532000021. The reversal of 55555531999909 is 90999913555555.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44230812890625 + 11324719109284 = 6650625^2 + 3365222^2 .

It is a cyclic number.

It is not a de Polignac number, because 55555531999909 - 2¹ = 55555531999907 is a prime.

Together with 55555531999907, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55555531999907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27777765999954 + 27777765999955.

It is an arithmetic number, because the mean of its divisors is an integer number (27777765999955).

Almost surely, 2^{55555531999909} is an apocalyptic number.

It is an amenable number.

55555531999909 is a deficient number, since it is larger than the sum of its proper divisors (1).

55555531999909 is an equidigital number, since it uses as much as digits as its factorization.

55555531999909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2767921875, while the sum is 79.

The spelling of 55555531999909 in words is "fifty-five trillion, five hundred fifty-five billion, five hundred thirty-one million, nine hundred ninety-nine thousand, nine hundred nine".