166491790 has 8 divisors (see below), whose sum is σ = 299685240. Its totient is φ = 66596712.

The previous prime is 166491763. The next prime is 166491791. The reversal of 166491790 is 97194661.

It is a happy number.

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

It is a super-2 number, since 2×166491790² = 55439032274808200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166491791) 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, 8324580 + ... + 8324599.

It is an arithmetic number, because the mean of its divisors is an integer number (37460655).

Almost surely, 2^166491790 is an apocalyptic number.

166491790 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

166491790 is a deficient number, since it is larger than the sum of its proper divisors (133193450).

166491790 is a wasteful number, since it uses less digits than its factorization.

166491790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16649186.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 166491790 is about 12903.1697656041. The cubic root of 166491790 is about 550.1286641135.

It can be divided in two parts, 166491 and 790, that added together give a square (167281 = 409²).

The spelling of 166491790 in words is "one hundred sixty-six million, four hundred ninety-one thousand, seven hundred ninety".