166666731 has 48 divisors (see below), whose sum is σ = 282223872. Its totient is φ = 85631040.

The previous prime is 166666729. The next prime is 166666783. The reversal of 166666731 is 137666661.

It is not a de Polignac number, because 166666731 - 2¹ = 166666729 is a prime.

It is a super-2 number, since 2×166666731² = 55555598444452722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (166666711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 271581 + ... + 272193.

It is an arithmetic number, because the mean of its divisors is an integer number (5879664).

Almost surely, 2^166666731 is an apocalyptic number.

166666731 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

166666731 is a deficient number, since it is larger than the sum of its proper divisors (115557141).

166666731 is a wasteful number, since it uses less digits than its factorization.

166666731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 752 (or 741 counting only the distinct ones).

The product of its digits is 163296, while the sum is 42.

The square root of 166666731 is about 12909.9469789771. The cubic root of 166666731 is about 550.3212789571.

The spelling of 166666731 in words is "one hundred sixty-six million, six hundred sixty-six thousand, seven hundred thirty-one".