66949381 has 2 divisors, whose sum is σ = 66949382. Its totient is φ = 66949380.

The previous prime is 66949373. The next prime is 66949387. The reversal of 66949381 is 18394966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41396356 + 25553025 = 6434^2 + 5055^2 .

It is a cyclic number.

It is not a de Polignac number, because 66949381 - 2³ = 66949373 is a prime.

It is a super-2 number, since 2×66949381² = 8964439232566322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66949387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33474690 + 33474691.

It is an arithmetic number, because the mean of its divisors is an integer number (33474691).

Almost surely, 2^66949381 is an apocalyptic number.

It is an amenable number.

66949381 is a deficient number, since it is larger than the sum of its proper divisors (1).

66949381 is an equidigital number, since it uses as much as digits as its factorization.

66949381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 46.

The square root of 66949381 is about 8182.2601400835. The cubic root of 66949381 is about 406.0524999449.

The spelling of 66949381 in words is "sixty-six million, nine hundred forty-nine thousand, three hundred eighty-one".