166451811840 has 560 divisors, whose sum is σ = 606478593600. Its totient is φ = 43786469376.

The previous prime is 166451811797. The next prime is 166451811899. The reversal of 166451811840 is 48118154661.

166451811840 is a `hidden beast` number, since 16 + 6 + 4 + 518 + 118 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 147432396 + ... + 147433524.

Almost surely, 2^166451811840 is an apocalyptic number.

166451811840 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 166451811840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (303239296800).

166451811840 is an abundant number, since it is smaller than the sum of its proper divisors (440026781760).

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

166451811840 is an frugal number, since it uses more digits than its factorization.

166451811840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1249 (or 1218 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The spelling of 166451811840 in words is "one hundred sixty-six billion, four hundred fifty-one million, eight hundred eleven thousand, eight hundred forty".