15551344221 has 16 divisors (see below), whose sum is σ = 24514435200. Its totient is φ = 8580051648.

The previous prime is 15551344189. The next prime is 15551344243. The reversal of 15551344221 is 12244315551.

It is not a de Polignac number, because 15551344221 - 2⁵ = 15551344189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15551344271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12767326 + ... + 12768543.

It is an arithmetic number, because the mean of its divisors is an integer number (1532152200).

Almost surely, 2^15551344221 is an apocalyptic number.

It is an amenable number.

15551344221 is a deficient number, since it is larger than the sum of its proper divisors (8963090979).

15551344221 is a wasteful number, since it uses less digits than its factorization.

15551344221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25535908.

The product of its digits is 24000, while the sum is 33.

Adding to 15551344221 its reverse (12244315551), we get a palindrome (27795659772).

The spelling of 15551344221 in words is "fifteen billion, five hundred fifty-one million, three hundred forty-four thousand, two hundred twenty-one".