166991553316 has 135 divisors (see below), whose sum is σ = 364805110677. Its totient is φ = 66691027200.

The previous prime is 166991553293. The next prime is 166991553329. The reversal of 166991553316 is 613355199661.

The square root of 166991553316 is 408646.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 7 ways, for example, as 24319154916 + 142672398400 = 155946^2 + 377720^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1653381666 + ... + 1653381766.

Almost surely, 2^166991553316 is an apocalyptic number.

166991553316 is the 408646-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166991553316

166991553316 is an abundant number, since it is smaller than the sum of its proper divisors (197813557361).

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

166991553316 is an frugal number, since it uses more digits than its factorization.

166991553316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 127 counting only the distinct ones).

The product of its digits is 3936600, while the sum is 55.

The spelling of 166991553316 in words is "one hundred sixty-six billion, nine hundred ninety-one million, five hundred fifty-three thousand, three hundred sixteen".