166861071238220 has 192 divisors, whose sum is σ = 383285626375680. Its totient is φ = 60774026969088.

The previous prime is 166861071238219. The next prime is 166861071238273. The reversal of 166861071238220 is 22832170168661.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1284934814 + ... + 1285064666.

It is an arithmetic number, because the mean of its divisors is an integer number (1996279304040).

Almost surely, 2^{166861071238220} is an apocalyptic number.

166861071238220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166861071238220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191642813187840).

166861071238220 is an abundant number, since it is smaller than the sum of its proper divisors (216424555137460).

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

166861071238220 is a wasteful number, since it uses less digits than its factorization.

166861071238220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130852 (or 130850 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 53.

The spelling of 166861071238220 in words is "one hundred sixty-six trillion, eight hundred sixty-one billion, seventy-one million, two hundred thirty-eight thousand, two hundred twenty".