66677778 has 48 divisors (see below), whose sum is σ = 148838976. Its totient is φ = 21561120.

The previous prime is 66677777. The next prime is 66677789. The reversal of 66677778 is 87777666.

It is a happy number.

It is a super-3 number, since 3×66677778³ (a number of 24 digits) contains 333 as substring.

It is a Curzon number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66677773) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 214243 + ... + 214553.

It is an arithmetic number, because the mean of its divisors is an integer number (3100812).

Almost surely, 2^66677778 is an apocalyptic number.

66677778 is an abundant number, since it is smaller than the sum of its proper divisors (82161198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66677778 is a wasteful number, since it uses less digits than its factorization.

66677778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639 (or 636 counting only the distinct ones).

The product of its digits is 4148928, while the sum is 54.

The square root of 66677778 is about 8165.6462083536. The cubic root of 66677778 is about 405.5026589114.

The spelling of 66677778 in words is "sixty-six million, six hundred seventy-seven thousand, seven hundred seventy-eight".