221311109991 has 16 divisors (see below), whose sum is σ = 302566376448. Its totient is φ = 143805144000.

The previous prime is 221311109947. The next prime is 221311110029. The reversal of 221311109991 is 199901113122.

It is not a de Polignac number, because 221311109991 - 2⁶ = 221311109927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221311109941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 726711 + ... + 985256.

It is an arithmetic number, because the mean of its divisors is an integer number (18910398528).

Almost surely, 2^221311109991 is an apocalyptic number.

221311109991 is a deficient number, since it is larger than the sum of its proper divisors (81255266457).

221311109991 is a wasteful number, since it uses less digits than its factorization.

221311109991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1713062.

The product of its (nonzero) digits is 8748, while the sum is 39.

The spelling of 221311109991 in words is "two hundred twenty-one billion, three hundred eleven million, one hundred nine thousand, nine hundred ninety-one".