166001011621020 has 144 divisors (see below), whose sum is σ = 505673014654080. Its totient is φ = 44079124174848.

The previous prime is 166001011621019. The next prime is 166001011621031. The reversal of 166001011621020 is 20126110100661.

166001011621020 is a `hidden beast` number, since 1 + 6 + 6 + 0 + 0 + 1 + 0 + 11 + 621 + 0 + 20 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 795464532 + ... + 795673188.

It is an arithmetic number, because the mean of its divisors is an integer number (3511618157320).

Almost surely, 2^{166001011621020} is an apocalyptic number.

166001011621020 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 166001011621020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252836507327040).

166001011621020 is an abundant number, since it is smaller than the sum of its proper divisors (339672003033060).

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

166001011621020 is a wasteful number, since it uses less digits than its factorization.

166001011621020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227404 (or 227399 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

Adding to 166001011621020 its reverse (20126110100661), we get a palindrome (186127121721681).

The spelling of 166001011621020 in words is "one hundred sixty-six trillion, one billion, eleven million, six hundred twenty-one thousand, twenty".