213127801666 has 16 divisors (see below), whose sum is σ = 351608552064. Its totient is φ = 96273769104.

The previous prime is 213127801609. The next prime is 213127801753. The reversal of 213127801666 is 666108721312.

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, 87203280 + ... + 87205723.

It is an arithmetic number, because the mean of its divisors is an integer number (21975534504).

Almost surely, 2^213127801666 is an apocalyptic number.

213127801666 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

213127801666 is a deficient number, since it is larger than the sum of its proper divisors (138480750398).

213127801666 is a wasteful number, since it uses less digits than its factorization.

213127801666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174409065.

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

The spelling of 213127801666 in words is "two hundred thirteen billion, one hundred twenty-seven million, eight hundred one thousand, six hundred sixty-six".