216425993 has 6 divisors (see below), whose sum is σ = 251760906. Its totient is φ = 185507952.

The previous prime is 216425981. The next prime is 216426047. The reversal of 216425993 is 399524612.

It can be written as a sum of positive squares in only one way, i.e., 120934009 + 95491984 = 10997^2 + 9772^2 .

It is not a de Polignac number, because 216425993 - 2¹² = 216421897 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 216425993.

It is not an unprimeable number, because it can be changed into a prime (216424993) 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, 2208380 + ... + 2208477.

It is an arithmetic number, because the mean of its divisors is an integer number (41960151).

Almost surely, 2^216425993 is an apocalyptic number.

It is an amenable number.

216425993 is a deficient number, since it is larger than the sum of its proper divisors (35334913).

216425993 is an equidigital number, since it uses as much as digits as its factorization.

216425993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4416871 (or 4416864 counting only the distinct ones).

The product of its digits is 116640, while the sum is 41.

The square root of 216425993 is about 14711.4238943754. The cubic root of 216425993 is about 600.3941789445.

The spelling of 216425993 in words is "two hundred sixteen million, four hundred twenty-five thousand, nine hundred ninety-three".