220497991 has 12 divisors (see below), whose sum is σ = 265344120. Its totient is φ = 182479920.

The previous prime is 220497989. The next prime is 220497997. The reversal of 220497991 is 199794022.

It is not a de Polignac number, because 220497991 - 2¹ = 220497989 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 (220497997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76165 + ... + 79006.

It is an arithmetic number, because the mean of its divisors is an integer number (22112010).

Almost surely, 2^220497991 is an apocalyptic number.

220497991 is a deficient number, since it is larger than the sum of its proper divisors (44846129).

220497991 is a wasteful number, since it uses less digits than its factorization.

220497991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155214 (or 155207 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 220497991 is about 14849.1747582147. The cubic root of 220497991 is about 604.1362270028.

The spelling of 220497991 in words is "two hundred twenty million, four hundred ninety-seven thousand, nine hundred ninety-one".