216819725 has 6 divisors (see below), whose sum is σ = 268856490. Its totient is φ = 173455760.

The previous prime is 216819721. The next prime is 216819727. The reversal of 216819725 is 527918612.

It can be written as a sum of positive squares in 3 ways, for example, as 61418569 + 155401156 = 7837^2 + 12466^2 .

It is not a de Polignac number, because 216819725 - 2² = 216819721 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216819721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4336370 + ... + 4336419.

It is an arithmetic number, because the mean of its divisors is an integer number (44809415).

Almost surely, 2^216819725 is an apocalyptic number.

216819725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

216819725 is a deficient number, since it is larger than the sum of its proper divisors (52036765).

216819725 is an equidigital number, since it uses as much as digits as its factorization.

216819725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8672799 (or 8672794 counting only the distinct ones).

The product of its digits is 60480, while the sum is 41.

The square root of 216819725 is about 14724.7996590786. The cubic root of 216819725 is about 600.7580465021.

The spelling of 216819725 in words is "two hundred sixteen million, eight hundred nineteen thousand, seven hundred twenty-five".