55421999 has 2 divisors, whose sum is σ = 55422000. Its totient is φ = 55421998.

The previous prime is 55421963. The next prime is 55422001. The reversal of 55421999 is 99912455.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55421999 is a prime.

Together with 55422001, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 12.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55421909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27710999 + 27711000.

It is an arithmetic number, because the mean of its divisors is an integer number (27711000).

Almost surely, 2^55421999 is an apocalyptic number.

55421999 is a deficient number, since it is larger than the sum of its proper divisors (1).

55421999 is an equidigital number, since it uses as much as digits as its factorization.

55421999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145800, while the sum is 44.

The square root of 55421999 is about 7444.5952878582. The cubic root of 55421999 is about 381.2654006499.

The spelling of 55421999 in words is "fifty-five million, four hundred twenty-one thousand, nine hundred ninety-nine".