66181949 has 2 divisors, whose sum is σ = 66181950. Its totient is φ = 66181948.

The previous prime is 66181943. The next prime is 66181957. The reversal of 66181949 is 94918166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40729924 + 25452025 = 6382^2 + 5045^2 .

It is a cyclic number.

It is not a de Polignac number, because 66181949 - 2²⁰ = 65133373 is a prime.

It is a super-3 number, since 3×66181949³ (a number of 24 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66181943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33090974 + 33090975.

It is an arithmetic number, because the mean of its divisors is an integer number (33090975).

Almost surely, 2^66181949 is an apocalyptic number.

It is an amenable number.

66181949 is a deficient number, since it is larger than the sum of its proper divisors (1).

66181949 is an equidigital number, since it uses as much as digits as its factorization.

66181949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 44.

The square root of 66181949 is about 8135.2288843031. The cubic root of 66181949 is about 404.4950247498.

The spelling of 66181949 in words is "sixty-six million, one hundred eighty-one thousand, nine hundred forty-nine".