221166764500 has 72 divisors (see below), whose sum is σ = 530931983400. Its totient is φ = 80424256000.

The previous prime is 221166764491. The next prime is 221166764501. The reversal of 221166764500 is 5467661122.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 53758132164 + 167408632336 = 231858^2 + 409156^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221166764501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1767325 + ... + 1888324.

It is an arithmetic number, because the mean of its divisors is an integer number (7374055325).

Almost surely, 2^221166764500 is an apocalyptic number.

221166764500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221166764500 is an abundant number, since it is smaller than the sum of its proper divisors (309765218900).

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

221166764500 is a wasteful number, since it uses less digits than its factorization.

221166764500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3655690 (or 3655667 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 221166764500 in words is "two hundred twenty-one billion, one hundred sixty-six million, seven hundred sixty-four thousand, five hundred".