221512508864 has 56 divisors (see below), whose sum is σ = 449447064528. Its totient is φ = 108293529600.

The previous prime is 221512508827. The next prime is 221512508869. The reversal of 221512508864 is 468805215122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221512508869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 300314 + ... + 730214.

It is an arithmetic number, because the mean of its divisors is an integer number (8025840438).

Almost surely, 2^221512508864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221512508864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (224723532264).

221512508864 is an abundant number, since it is smaller than the sum of its proper divisors (227934555664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221512508864 is an equidigital number, since it uses as much as digits as its factorization.

221512508864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430093 (or 430083 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 44.

The spelling of 221512508864 in words is "two hundred twenty-one billion, five hundred twelve million, five hundred eight thousand, eight hundred sixty-four".