221801437764 has 81 divisors (see below), whose sum is σ = 571829031319. Its totient is φ = 72489855360.

The previous prime is 221801437729. The next prime is 221801437787. The reversal of 221801437764 is 467734108122.

The square root of 221801437764 is 470958.

It is a perfect power (a square), and thus also a powerful number.

221801437764 is a `hidden beast` number, since 2 + 218 + 0 + 1 + 4 + 377 + 64 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5397840900 + 216403596864 = 73470^2 + 465192^2 .

It is a Duffinian number.

It is an unprimeable number.

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 26 ways as a sum of consecutive naturals, for example, 149763904 + ... + 149765384.

Almost surely, 2^221801437764 is an apocalyptic number.

221801437764 is the 470958-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221801437764

221801437764 is an abundant number, since it is smaller than the sum of its proper divisors (350027593555).

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

221801437764 is an equidigital number, since it uses as much as digits as its factorization.

221801437764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3078 (or 1539 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 45.

The spelling of 221801437764 in words is "two hundred twenty-one billion, eight hundred one million, four hundred thirty-seven thousand, seven hundred sixty-four".