491287886221 has 4 divisors (see below), whose sum is σ = 535950421344. Its totient is φ = 446625351100.

The previous prime is 491287886189. The next prime is 491287886233. The reversal of 491287886221 is 122688782194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 491287886221 - 2⁵ = 491287886189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491287886251) 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, 22331267545 + ... + 22331267566.

It is an arithmetic number, because the mean of its divisors is an integer number (133987605336).

Almost surely, 2^491287886221 is an apocalyptic number.

It is an amenable number.

491287886221 is a deficient number, since it is larger than the sum of its proper divisors (44662535123).

491287886221 is a wasteful number, since it uses less digits than its factorization.

491287886221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44662535122.

The product of its digits is 6193152, while the sum is 58.

The spelling of 491287886221 in words is "four hundred ninety-one billion, two hundred eighty-seven million, eight hundred eighty-six thousand, two hundred twenty-one".