66541949 has 4 divisors (see below), whose sum is σ = 66563964. Its totient is φ = 66519936.

The previous prime is 66541913. The next prime is 66541957. The reversal of 66541949 is 94914566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94914566 = 2 ⋅47457283.

It can be written as a sum of positive squares in 2 ways, for example, as 25351225 + 41190724 = 5035^2 + 6418^2 .

It is a cyclic number.

It is not a de Polignac number, because 66541949 - 2⁸ = 66541693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66541999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5582 + ... + 12815.

It is an arithmetic number, because the mean of its divisors is an integer number (16640991).

Almost surely, 2^66541949 is an apocalyptic number.

It is an amenable number.

66541949 is a deficient number, since it is larger than the sum of its proper divisors (22015).

66541949 is a wasteful number, since it uses less digits than its factorization.

66541949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22014.

The product of its digits is 233280, while the sum is 44.

The square root of 66541949 is about 8157.3248678718. The cubic root of 66541949 is about 405.2271225178.

The spelling of 66541949 in words is "sixty-six million, five hundred forty-one thousand, nine hundred forty-nine".