55123221421 has 4 divisors (see below), whose sum is σ = 55658398432. Its totient is φ = 54588044412.

The previous prime is 55123221407. The next prime is 55123221427. The reversal of 55123221421 is 12412232155.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12412232155 = 5 ⋅2482446431.

It is a cyclic number.

It is not a de Polignac number, because 55123221421 - 2¹¹ = 55123219373 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55123221421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55123221427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267588351 + ... + 267588556.

It is an arithmetic number, because the mean of its divisors is an integer number (13914599608).

Almost surely, 2^55123221421 is an apocalyptic number.

It is an amenable number.

55123221421 is a deficient number, since it is larger than the sum of its proper divisors (535177011).

55123221421 is a wasteful number, since it uses less digits than its factorization.

55123221421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535177010.

The product of its digits is 4800, while the sum is 28.

Adding to 55123221421 its reverse (12412232155), we get a palindrome (67535453576).

The spelling of 55123221421 in words is "fifty-five billion, one hundred twenty-three million, two hundred twenty-one thousand, four hundred twenty-one".