66791537 has 2 divisors, whose sum is σ = 66791538. Its totient is φ = 66791536.

The previous prime is 66791531. The next prime is 66791539. The reversal of 66791537 is 73519766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 36772096 + 30019441 = 6064^2 + 5479^2 .

It is a cyclic number.

It is not a de Polignac number, because 66791537 - 2¹⁴ = 66775153 is a prime.

It is a super-2 number, since 2×66791537² = 8922218829644738, which contains 22 as substring.

Together with 66791539, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66791531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33395768 + 33395769.

It is an arithmetic number, because the mean of its divisors is an integer number (33395769).

Almost surely, 2^66791537 is an apocalyptic number.

It is an amenable number.

66791537 is a deficient number, since it is larger than the sum of its proper divisors (1).

66791537 is an equidigital number, since it uses as much as digits as its factorization.

66791537 is an odious number, because the sum of its binary digits is odd.

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

The square root of 66791537 is about 8172.6089469642. The cubic root of 66791537 is about 405.7331373371.

The spelling of 66791537 in words is "sixty-six million, seven hundred ninety-one thousand, five hundred thirty-seven".