66994481 has 2 divisors, whose sum is σ = 66994482. Its totient is φ = 66994480.

The previous prime is 66994453. The next prime is 66994489. The reversal of 66994481 is 18449966.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66994225 + 256 = 8185^2 + 16^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66994481 is a prime.

It is a super-2 number, since 2×66994481² = 8976520968918722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66994489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33497240 + 33497241.

It is an arithmetic number, because the mean of its divisors is an integer number (33497241).

Almost surely, 2^66994481 is an apocalyptic number.

It is an amenable number.

66994481 is a deficient number, since it is larger than the sum of its proper divisors (1).

66994481 is an equidigital number, since it uses as much as digits as its factorization.

66994481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 47.

The square root of 66994481 is about 8185.0156383479. The cubic root of 66994481 is about 406.1436576568.

The spelling of 66994481 in words is "sixty-six million, nine hundred ninety-four thousand, four hundred eighty-one".