55420442221 has 16 divisors (see below), whose sum is σ = 59152518000. Its totient is φ = 51742179328.

The previous prime is 55420442137. The next prime is 55420442227. The reversal of 55420442221 is 12224402455.

It can be written as a sum of positive squares in 8 ways, for example, as 8108102025 + 47312340196 = 90045^2 + 217514^2 .

It is a cyclic number.

It is not a de Polignac number, because 55420442221 - 2¹⁵ = 55420409453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55420442227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1299525 + ... + 1341493.

It is an arithmetic number, because the mean of its divisors is an integer number (3697032375).

Almost surely, 2^55420442221 is an apocalyptic number.

It is an amenable number.

55420442221 is a deficient number, since it is larger than the sum of its proper divisors (3732075779).

55420442221 is a wasteful number, since it uses less digits than its factorization.

55420442221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42608.

The product of its (nonzero) digits is 25600, while the sum is 31.

Adding to 55420442221 its reverse (12224402455), we get a palindrome (67644844676).

The spelling of 55420442221 in words is "fifty-five billion, four hundred twenty million, four hundred forty-two thousand, two hundred twenty-one".