91003220221 has 4 divisors (see below), whose sum is σ = 91059780700. Its totient is φ = 90946659744.

The previous prime is 91003220201. The next prime is 91003220239. The reversal of 91003220221 is 12202230019.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 48571752100 + 42431468121 = 220390^2 + 205989^2 .

It is a cyclic number.

It is not a de Polignac number, because 91003220221 - 2¹⁹ = 91002695933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91003220192 and 91003220201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91003220201) 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, 28277826 + ... + 28281043.

It is an arithmetic number, because the mean of its divisors is an integer number (22764945175).

Almost surely, 2^91003220221 is an apocalyptic number.

It is an amenable number.

91003220221 is a deficient number, since it is larger than the sum of its proper divisors (56560479).

91003220221 is a wasteful number, since it uses less digits than its factorization.

91003220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56560478.

The product of its (nonzero) digits is 432, while the sum is 22.

The spelling of 91003220221 in words is "ninety-one billion, three million, two hundred twenty thousand, two hundred twenty-one".