166209331 has 4 divisors (see below), whose sum is σ = 166253472. Its totient is φ = 166165192.

The previous prime is 166209301. The next prime is 166209467. The reversal of 166209331 is 133902661.

166209331 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 133902661 = 3607 ⋅37123.

It is a cyclic number.

It is not a de Polignac number, because 166209331 - 2⁵ = 166209299 is a prime.

It is a super-2 number, since 2×166209331² = 55251083422935122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 166209293 and 166209302.

It is not an unprimeable number, because it can be changed into a prime (166209301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15835 + ... + 24148.

It is an arithmetic number, because the mean of its divisors is an integer number (41563368).

Almost surely, 2^166209331 is an apocalyptic number.

166209331 is a deficient number, since it is larger than the sum of its proper divisors (44141).

166209331 is an equidigital number, since it uses as much as digits as its factorization.

166209331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44140.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 166209331 is about 12892.2197855916. The cubic root of 166209331 is about 549.8173840010.

The spelling of 166209331 in words is "one hundred sixty-six million, two hundred nine thousand, three hundred thirty-one".