55421213 has 2 divisors, whose sum is σ = 55421214. Its totient is φ = 55421212.

The previous prime is 55421209. The next prime is 55421221. The reversal of 55421213 is 31212455.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45454564 + 9966649 = 6742^2 + 3157^2 .

It is a cyclic number.

It is not a de Polignac number, because 55421213 - 2² = 55421209 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55421203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27710606 + 27710607.

It is an arithmetic number, because the mean of its divisors is an integer number (27710607).

Almost surely, 2^55421213 is an apocalyptic number.

It is an amenable number.

55421213 is a deficient number, since it is larger than the sum of its proper divisors (1).

55421213 is an equidigital number, since it uses as much as digits as its factorization.

55421213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1200, while the sum is 23.

The square root of 55421213 is about 7444.5424976959. The cubic root of 55421213 is about 381.2635982608.

Adding to 55421213 its reverse (31212455), we get a palindrome (86633668).

The spelling of 55421213 in words is "fifty-five million, four hundred twenty-one thousand, two hundred thirteen".