66723157 has 2 divisors, whose sum is σ = 66723158. Its totient is φ = 66723156.

The previous prime is 66723121. The next prime is 66723179. The reversal of 66723157 is 75132766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66683556 + 39601 = 8166^2 + 199^2 .

It is a cyclic number.

It is not a de Polignac number, because 66723157 - 2¹⁵ = 66690389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66723257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33361578 + 33361579.

It is an arithmetic number, because the mean of its divisors is an integer number (33361579).

Almost surely, 2^66723157 is an apocalyptic number.

It is an amenable number.

66723157 is a deficient number, since it is larger than the sum of its proper divisors (1).

66723157 is an equidigital number, since it uses as much as digits as its factorization.

66723157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52920, while the sum is 37.

The square root of 66723157 is about 8168.4243890728. The cubic root of 66723157 is about 405.5946292440.

The spelling of 66723157 in words is "sixty-six million, seven hundred twenty-three thousand, one hundred fifty-seven".