65218381 has 2 divisors, whose sum is σ = 65218382. Its totient is φ = 65218380.

The previous prime is 65218369. The next prime is 65218397. The reversal of 65218381 is 18381256.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55264356 + 9954025 = 7434^2 + 3155^2 .

It is a cyclic number.

It is not a de Polignac number, because 65218381 - 2⁷ = 65218253 is a prime.

It is a super-2 number, since 2×65218381² = 8506874440522322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65218301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32609190 + 32609191.

It is an arithmetic number, because the mean of its divisors is an integer number (32609191).

Almost surely, 2^65218381 is an apocalyptic number.

It is an amenable number.

65218381 is a deficient number, since it is larger than the sum of its proper divisors (1).

65218381 is an equidigital number, since it uses as much as digits as its factorization.

65218381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 34.

The square root of 65218381 is about 8075.7898065762. The cubic root of 65218381 is about 402.5223546346.

The spelling of 65218381 in words is "sixty-five million, two hundred eighteen thousand, three hundred eighty-one".