66782491 has 4 divisors (see below), whose sum is σ = 68042592. Its totient is φ = 65522392.

The previous prime is 66782489. The next prime is 66782503. The reversal of 66782491 is 19428766.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66782491 - 2¹ = 66782489 is a prime.

It is a super-2 number, since 2×66782491² = 8919802208330162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66782461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 629971 + ... + 630076.

It is an arithmetic number, because the mean of its divisors is an integer number (17010648).

Almost surely, 2^66782491 is an apocalyptic number.

66782491 is a deficient number, since it is larger than the sum of its proper divisors (1260101).

66782491 is a wasteful number, since it uses less digits than its factorization.

66782491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1260100.

The product of its digits is 145152, while the sum is 43.

The square root of 66782491 is about 8172.0554941826. The cubic root of 66782491 is about 405.7148195091.

The spelling of 66782491 in words is "sixty-six million, seven hundred eighty-two thousand, four hundred ninety-one".