66526381 has 2 divisors, whose sum is σ = 66526382. Its totient is φ = 66526380.

The previous prime is 66526379. The next prime is 66526441. The reversal of 66526381 is 18362566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44342281 + 22184100 = 6659^2 + 4710^2 .

It is a cyclic number.

It is not a de Polignac number, because 66526381 - 2¹ = 66526379 is a prime.

It is a super-2 number, since 2×66526381² = 8851518737914322, which contains 22 as substring.

Together with 66526379, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 66526381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66520381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33263190 + 33263191.

It is an arithmetic number, because the mean of its divisors is an integer number (33263191).

Almost surely, 2^66526381 is an apocalyptic number.

It is an amenable number.

66526381 is a deficient number, since it is larger than the sum of its proper divisors (1).

66526381 is an equidigital number, since it uses as much as digits as its factorization.

66526381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 37.

The square root of 66526381 is about 8156.3705776528. The cubic root of 66526381 is about 405.1955180538.

The spelling of 66526381 in words is "sixty-six million, five hundred twenty-six thousand, three hundred eighty-one".