216162581 has 2 divisors, whose sum is σ = 216162582. Its totient is φ = 216162580.

The previous prime is 216162571. The next prime is 216162637. The reversal of 216162581 is 185261612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 214622500 + 1540081 = 14650^2 + 1241^2 .

It is a cyclic number.

It is not a de Polignac number, because 216162581 - 2⁶ = 216162517 is a prime.

It is a super-2 number, since 2×216162581² = 93452522849163122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216162521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108081290 + 108081291.

It is an arithmetic number, because the mean of its divisors is an integer number (108081291).

Almost surely, 2^216162581 is an apocalyptic number.

It is an amenable number.

216162581 is a deficient number, since it is larger than the sum of its proper divisors (1).

216162581 is an equidigital number, since it uses as much as digits as its factorization.

216162581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 216162581 is about 14702.4685342292. The cubic root of 216162581 is about 600.1505002093.

The spelling of 216162581 in words is "two hundred sixteen million, one hundred sixty-two thousand, five hundred eighty-one".