666627779 has 8 divisors (see below), whose sum is σ = 685162800. Its totient is φ = 648120096.

The previous prime is 666627769. The next prime is 666627781. The reversal of 666627779 is 977726666.

It is a happy number.

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 666627779 - 2⁴ = 666627763 is a prime.

It is a super-3 number, since 3×666627779³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666627719) 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, 48797 + ... + 60945.

It is an arithmetic number, because the mean of its divisors is an integer number (85645350).

Almost surely, 2^666627779 is an apocalyptic number.

666627779 is a deficient number, since it is larger than the sum of its proper divisors (18535021).

666627779 is a wasteful number, since it uses less digits than its factorization.

666627779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13669.

The product of its digits is 8001504, while the sum is 56.

The square root of 666627779 is about 25819.1359073072. The cubic root of 666627779 is about 873.5634786531.

The spelling of 666627779 in words is "six hundred sixty-six million, six hundred twenty-seven thousand, seven hundred seventy-nine".