55394021 has 2 divisors, whose sum is σ = 55394022. Its totient is φ = 55394020.

The previous prime is 55393999. The next prime is 55394023. The reversal of 55394021 is 12049355.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39513796 + 15880225 = 6286^2 + 3985^2 .

It is a cyclic number.

It is not a de Polignac number, because 55394021 - 2²² = 51199717 is a prime.

It is a Sophie Germain prime.

Together with 55394023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55394023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27697010 + 27697011.

It is an arithmetic number, because the mean of its divisors is an integer number (27697011).

Almost surely, 2^55394021 is an apocalyptic number.

It is an amenable number.

55394021 is a deficient number, since it is larger than the sum of its proper divisors (1).

55394021 is an equidigital number, since it uses as much as digits as its factorization.

55394021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 55394021 is about 7442.7159693220. The cubic root of 55394021 is about 381.2012333575.

The spelling of 55394021 in words is "fifty-five million, three hundred ninety-four thousand, twenty-one".