166720005 has 32 divisors (see below), whose sum is σ = 298072320. Its totient is φ = 88413120.

The previous prime is 166719997. The next prime is 166720007. The reversal of 166720005 is 500027661.

It is not a de Polignac number, because 166720005 - 2³ = 166719997 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166720007) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21024 + ... + 27846.

It is an arithmetic number, because the mean of its divisors is an integer number (9314760).

Almost surely, 2^166720005 is an apocalyptic number.

166720005 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166720005 is a deficient number, since it is larger than the sum of its proper divisors (131352315).

166720005 is a wasteful number, since it uses less digits than its factorization.

166720005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7018 (or 7012 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 166720005 is about 12912.0101068734. The cubic root of 166720005 is about 550.3799083197.

Adding to 166720005 its reverse (500027661), we get a palindrome (666747666).

The spelling of 166720005 in words is "one hundred sixty-six million, seven hundred twenty thousand, five".