166642631 has 4 divisors (see below), whose sum is σ = 166820664. Its totient is φ = 166464600.

The previous prime is 166642591. The next prime is 166642633. The reversal of 166642631 is 136246661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166642631 is a prime.

It is a super-2 number, since 2×166642631² = 55539532933204322, 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 = 166642591 and 166642600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166642633) 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 3 ways as a sum of consecutive naturals, for example, 87605 + ... + 89486.

It is an arithmetic number, because the mean of its divisors is an integer number (41705166).

Almost surely, 2^166642631 is an apocalyptic number.

166642631 is a deficient number, since it is larger than the sum of its proper divisors (178033).

166642631 is an equidigital number, since it uses as much as digits as its factorization.

166642631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178032.

The product of its digits is 31104, while the sum is 35.

The square root of 166642631 is about 12909.0135564264. The cubic root of 166642631 is about 550.2947522031.

The spelling of 166642631 in words is "one hundred sixty-six million, six hundred forty-two thousand, six hundred thirty-one".