166320509 has 8 divisors (see below), whose sum is σ = 175347840. Its totient is φ = 157320576.

The previous prime is 166320493. The next prime is 166320523. The reversal of 166320509 is 905023661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166320509 - 2⁴ = 166320493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166320109) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6284 + ... + 19290.

It is an arithmetic number, because the mean of its divisors is an integer number (21918480).

Almost surely, 2^166320509 is an apocalyptic number.

166320509 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

166320509 is a deficient number, since it is larger than the sum of its proper divisors (9027331).

166320509 is a wasteful number, since it uses less digits than its factorization.

166320509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13699.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 166320509 is about 12896.5308901270. The cubic root of 166320509 is about 549.9399482644.

The spelling of 166320509 in words is "one hundred sixty-six million, three hundred twenty thousand, five hundred nine".