221371393551 has 16 divisors (see below), whose sum is σ = 367994005248. Its totient is φ = 114998126400.

The previous prime is 221371393547. The next prime is 221371393561. The reversal of 221371393551 is 155393173122.

221371393551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221371393551 - 2² = 221371393547 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221371393561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 479158630 + ... + 479159091.

It is an arithmetic number, because the mean of its divisors is an integer number (22999625328).

Almost surely, 2^221371393551 is an apocalyptic number.

221371393551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

221371393551 is a deficient number, since it is larger than the sum of its proper divisors (146622611697).

221371393551 is a wasteful number, since it uses less digits than its factorization.

221371393551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 958317742.

The product of its digits is 170100, while the sum is 42.

The spelling of 221371393551 in words is "two hundred twenty-one billion, three hundred seventy-one million, three hundred ninety-three thousand, five hundred fifty-one".