15221405555 has 4 divisors (see below), whose sum is σ = 18265686672. Its totient is φ = 12177124440.

The previous prime is 15221405539. The next prime is 15221405557. The reversal of 15221405555 is 55550412251.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55550412251 = 14251 ⋅3898001.

It is not a de Polignac number, because 15221405555 - 2⁴ = 15221405539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15221405557) 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, 1522140551 + ... + 1522140560.

It is an arithmetic number, because the mean of its divisors is an integer number (4566421668).

Almost surely, 2^15221405555 is an apocalyptic number.

15221405555 is a deficient number, since it is larger than the sum of its proper divisors (3044281117).

15221405555 is an equidigital number, since it uses as much as digits as its factorization.

15221405555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3044281116.

The product of its (nonzero) digits is 50000, while the sum is 35.

The spelling of 15221405555 in words is "fifteen billion, two hundred twenty-one million, four hundred five thousand, five hundred fifty-five".