66669878 has 16 divisors (see below), whose sum is σ = 110593296. Its totient is φ = 29888640.

The previous prime is 66669857. The next prime is 66669899. The reversal of 66669878 is 87896666.

It is an interprime number because it is at equal distance from previous prime (66669857) and next prime (66669899).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19151 + ... + 22362.

It is an arithmetic number, because the mean of its divisors is an integer number (6912081).

Almost surely, 2^66669878 is an apocalyptic number.

66669878 is a deficient number, since it is larger than the sum of its proper divisors (43923418).

66669878 is a wasteful number, since it uses less digits than its factorization.

66669878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41599.

The product of its digits is 5225472, while the sum is 56.

The square root of 66669878 is about 8165.1624601106. The cubic root of 66669878 is about 405.4866435930.

The spelling of 66669878 in words is "sixty-six million, six hundred sixty-nine thousand, eight hundred seventy-eight".