221381521405 has 16 divisors (see below), whose sum is σ = 291052367424. Its totient is φ = 160313726080.

The previous prime is 221381521379. The next prime is 221381521421. The reversal of 221381521405 is 504125183122.

It is not a de Polignac number, because 221381521405 - 2²⁷ = 221247303677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8624779 + ... + 8650408.

It is an arithmetic number, because the mean of its divisors is an integer number (18190772964).

Almost surely, 2^221381521405 is an apocalyptic number.

It is an amenable number.

221381521405 is a deficient number, since it is larger than the sum of its proper divisors (69670846019).

221381521405 is a wasteful number, since it uses less digits than its factorization.

221381521405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17275436.

The product of its (nonzero) digits is 19200, while the sum is 34.

The spelling of 221381521405 in words is "two hundred twenty-one billion, three hundred eighty-one million, five hundred twenty-one thousand, four hundred five".