55808821 has 2 divisors, whose sum is σ = 55808822. Its totient is φ = 55808820.

The previous prime is 55808803. The next prime is 55808843. The reversal of 55808821 is 12880855.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55800900 + 7921 = 7470^2 + 89^2 .

It is a cyclic number.

It is not a de Polignac number, because 55808821 - 2⁹ = 55808309 is a prime.

It is a super-2 number, since 2×55808821² = 6229249002820082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55808861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27904410 + 27904411.

It is an arithmetic number, because the mean of its divisors is an integer number (27904411).

Almost surely, 2^55808821 is an apocalyptic number.

It is an amenable number.

55808821 is a deficient number, since it is larger than the sum of its proper divisors (1).

55808821 is an equidigital number, since it uses as much as digits as its factorization.

55808821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25600, while the sum is 37.

The square root of 55808821 is about 7470.5301686025. The cubic root of 55808821 is about 382.1503684219.

The spelling of 55808821 in words is "fifty-five million, eight hundred eight thousand, eight hundred twenty-one".