66149923 has 4 divisors (see below), whose sum is σ = 75599920. Its totient is φ = 56699928.

The previous prime is 66149903. The next prime is 66149947. The reversal of 66149923 is 32994166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32994166 = 2 ⋅16497083.

It is a cyclic number.

It is not a de Polignac number, because 66149923 - 2⁹ = 66149411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66149903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4724988 + ... + 4725001.

It is an arithmetic number, because the mean of its divisors is an integer number (18899980).

Almost surely, 2^66149923 is an apocalyptic number.

66149923 is a deficient number, since it is larger than the sum of its proper divisors (9449997).

66149923 is an equidigital number, since it uses as much as digits as its factorization.

66149923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9449996.

The product of its digits is 69984, while the sum is 40.

The square root of 66149923 is about 8133.2602933879. The cubic root of 66149923 is about 404.4297680447.

The spelling of 66149923 in words is "sixty-six million, one hundred forty-nine thousand, nine hundred twenty-three".