66513481 has 2 divisors, whose sum is σ = 66513482. Its totient is φ = 66513480.

The previous prime is 66513479. The next prime is 66513487. The reversal of 66513481 is 18431566.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 34703881 + 31809600 = 5891^2 + 5640^2 .

It is a cyclic number.

It is not a de Polignac number, because 66513481 - 2¹ = 66513479 is a prime.

It is a super-2 number, since 2×66513481² = 8848086309474722, which contains 22 as substring.

Together with 66513479, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (66513487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33256740 + 33256741.

It is an arithmetic number, because the mean of its divisors is an integer number (33256741).

Almost surely, 2^66513481 is an apocalyptic number.

It is an amenable number.

66513481 is a deficient number, since it is larger than the sum of its proper divisors (1).

66513481 is an equidigital number, since it uses as much as digits as its factorization.

66513481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 34.

The square root of 66513481 is about 8155.5797464068. The cubic root of 66513481 is about 405.1693261382.

The spelling of 66513481 in words is "sixty-six million, five hundred thirteen thousand, four hundred eighty-one".