66157973 has 4 divisors (see below), whose sum is σ = 75609120. Its totient is φ = 56706828.

The previous prime is 66157967. The next prime is 66158003. The reversal of 66157973 is 37975166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 37975166 = 2 ⋅18987583.

It is a cyclic number.

It is not a de Polignac number, because 66157973 - 2⁴ = 66157957 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 (66157673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4725563 + ... + 4725576.

It is an arithmetic number, because the mean of its divisors is an integer number (18902280).

Almost surely, 2^66157973 is an apocalyptic number.

It is an amenable number.

66157973 is a deficient number, since it is larger than the sum of its proper divisors (9451147).

66157973 is an equidigital number, since it uses as much as digits as its factorization.

66157973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9451146.

The product of its digits is 238140, while the sum is 44.

The square root of 66157973 is about 8133.7551598262. The cubic root of 66157973 is about 404.4461728386.

The spelling of 66157973 in words is "sixty-six million, one hundred fifty-seven thousand, nine hundred seventy-three".