55501421 has 2 divisors, whose sum is σ = 55501422. Its totient is φ = 55501420.

The previous prime is 55501403. The next prime is 55501423. The reversal of 55501421 is 12410555.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 35832196 + 19669225 = 5986^2 + 4435^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55501421 is a prime.

Together with 55501423, 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 (55501423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27750710 + 27750711.

It is an arithmetic number, because the mean of its divisors is an integer number (27750711).

Almost surely, 2^55501421 is an apocalyptic number.

It is an amenable number.

55501421 is a deficient number, since it is larger than the sum of its proper divisors (1).

55501421 is an equidigital number, since it uses as much as digits as its factorization.

55501421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 55501421 is about 7449.9275835407. The cubic root of 55501421 is about 381.4474367134.

Adding to 55501421 its reverse (12410555), we get a palindrome (67911976).

The spelling of 55501421 in words is "fifty-five million, five hundred one thousand, four hundred twenty-one".