66761257 has 8 divisors (see below), whose sum is σ = 67321800. Its totient is φ = 66203520.

The previous prime is 66761237. The next prime is 66761263. The reversal of 66761257 is 75216766.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3701776 + 63059481 = 1924^2 + 7941^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66761257 - 2⁷ = 66761129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66761237) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80907 + ... + 81727.

It is an arithmetic number, because the mean of its divisors is an integer number (8415225).

Almost surely, 2^66761257 is an apocalyptic number.

It is an amenable number.

66761257 is a deficient number, since it is larger than the sum of its proper divisors (560543).

66761257 is a wasteful number, since it uses less digits than its factorization.

66761257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1403.

The product of its digits is 105840, while the sum is 40.

The square root of 66761257 is about 8170.7562073531. The cubic root of 66761257 is about 405.6718149152.

The spelling of 66761257 in words is "sixty-six million, seven hundred sixty-one thousand, two hundred fifty-seven".