166121280 has 560 divisors, whose sum is σ = 697047120. Its totient is φ = 37158912.

The previous prime is 166121261. The next prime is 166121321. The reversal of 166121280 is 82121661.

166121280 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 1871424 + 164249856 = 1368^2 + 12816^2 .

It is a super-3 number, since 3×166121280³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5728306 + ... + 5728334.

It is an arithmetic number, because the mean of its divisors is an integer number (1244727).

Almost surely, 2^166121280 is an apocalyptic number.

166121280 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 166121280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (348523560).

166121280 is an abundant number, since it is smaller than the sum of its proper divisors (530925840).

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

166121280 is a wasteful number, since it uses less digits than its factorization.

166121280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 166121280 is about 12888.8044441678. The cubic root of 166121280 is about 549.7202764928.

The spelling of 166121280 in words is "one hundred sixty-six million, one hundred twenty-one thousand, two hundred eighty".