66791787 has 8 divisors (see below), whose sum is σ = 89157120. Its totient is φ = 44477160.

The previous prime is 66791779. The next prime is 66791797. The reversal of 66791787 is 78719766.

It is a happy number.

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

It is not a de Polignac number, because 66791787 - 2³ = 66791779 is a prime.

It is a super-2 number, since 2×66791787² = 8922285621306738, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66791737) 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 7 ways as a sum of consecutive naturals, for example, 9487 + ... + 14952.

It is an arithmetic number, because the mean of its divisors is an integer number (11144640).

Almost surely, 2^66791787 is an apocalyptic number.

66791787 is a deficient number, since it is larger than the sum of its proper divisors (22365333).

66791787 is a wasteful number, since it uses less digits than its factorization.

66791787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25353.

The product of its digits is 889056, while the sum is 51.

The square root of 66791787 is about 8172.6242419433. The cubic root of 66791787 is about 405.7336435547.

The spelling of 66791787 in words is "sixty-six million, seven hundred ninety-one thousand, seven hundred eighty-seven".