221958765625 has 21 divisors (see below), whose sum is σ = 277518537561. Its totient is φ = 177519900000.

The previous prime is 221958765593. The next prime is 221958765647. The reversal of 221958765625 is 526567859122.

The square root of 221958765625 is 471125.

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

It can be written as a sum of positive squares in 10 ways, for example, as 220962984489 + 995781136 = 470067^2 + 31556^2 .

It is not a de Polignac number, because 221958765625 - 2⁵ = 221958765593 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221958765625.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 58888741 + ... + 58892509.

Almost surely, 2^221958765625 is an apocalyptic number.

221958765625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

221958765625 is the 471125-th square number.

221958765625 is the 235563-rd centered octagonal number.

It is an amenable number.

221958765625 is a deficient number, since it is larger than the sum of its proper divisors (55559771936).

221958765625 is an frugal number, since it uses more digits than its factorization.

221958765625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7568 (or 3774 counting only the distinct ones).

The product of its digits is 18144000, while the sum is 58.

The spelling of 221958765625 in words is "two hundred twenty-one billion, nine hundred fifty-eight million, seven hundred sixty-five thousand, six hundred twenty-five".