666777838 has 8 divisors (see below), whose sum is σ = 1001309832. Its totient is φ = 333007896.

The previous prime is 666777809. The next prime is 666777869. The reversal of 666777838 is 838777666.

It is a happy number.

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

It is a super-3 number, since 3×666777838³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188320 + ... + 191827.

It is an arithmetic number, because the mean of its divisors is an integer number (125163729).

Almost surely, 2^666777838 is an apocalyptic number.

666777838 is a deficient number, since it is larger than the sum of its proper divisors (334531994).

666777838 is a wasteful number, since it uses less digits than its factorization.

666777838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381026.

The product of its digits is 14224896, while the sum is 58.

The square root of 666777838 is about 25822.0417085869. The cubic root of 666777838 is about 873.6290205899.

The spelling of 666777838 in words is "six hundred sixty-six million, seven hundred seventy-seven thousand, eight hundred thirty-eight".