55677821 has 2 divisors, whose sum is σ = 55677822. Its totient is φ = 55677820.

The previous prime is 55677781. The next prime is 55677823. The reversal of 55677821 is 12877655.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28783225 + 26894596 = 5365^2 + 5186^2 .

It is a cyclic number.

It is not a de Polignac number, because 55677821 - 2²² = 51483517 is a prime.

Together with 55677823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55677823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27838910 + 27838911.

It is an arithmetic number, because the mean of its divisors is an integer number (27838911).

Almost surely, 2^55677821 is an apocalyptic number.

It is an amenable number.

55677821 is a deficient number, since it is larger than the sum of its proper divisors (1).

55677821 is an equidigital number, since it uses as much as digits as its factorization.

55677821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 117600, while the sum is 41.

The square root of 55677821 is about 7461.7572327167. The cubic root of 55677821 is about 381.8511270806.

The spelling of 55677821 in words is "fifty-five million, six hundred seventy-seven thousand, eight hundred twenty-one".