168421637 has 4 divisors (see below), whose sum is σ = 169362720. Its totient is φ = 167480556.

The previous prime is 168421621. The next prime is 168421639. The reversal of 168421637 is 736124861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 736124861 = 173 ⋅4255057.

It is a cyclic number.

It is not a de Polignac number, because 168421637 - 2⁴ = 168421621 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 168421637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168421639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 470273 + ... + 470630.

It is an arithmetic number, because the mean of its divisors is an integer number (42340680).

Almost surely, 2^168421637 is an apocalyptic number.

It is an amenable number.

168421637 is a deficient number, since it is larger than the sum of its proper divisors (941083).

168421637 is an equidigital number, since it uses as much as digits as its factorization.

168421637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 941082.

The product of its digits is 48384, while the sum is 38.

The square root of 168421637 is about 12977.7362047470. The cubic root of 168421637 is about 552.2460625390.

The spelling of 168421637 in words is "one hundred sixty-eight million, four hundred twenty-one thousand, six hundred thirty-seven".