168181840 has 20 divisors (see below), whose sum is σ = 391022964. Its totient is φ = 67272704.

The previous prime is 168181831. The next prime is 168181841. The reversal of 168181840 is 48181861.

It can be written as a sum of positive squares in 2 ways, for example, as 125619264 + 42562576 = 11208^2 + 6524^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 168181840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168181841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1051057 + ... + 1051216.

Almost surely, 2^168181840 is an apocalyptic number.

168181840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

168181840 is an abundant number, since it is smaller than the sum of its proper divisors (222841124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

168181840 is a wasteful number, since it uses less digits than its factorization.

168181840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2102286 (or 2102280 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 37.

The square root of 168181840 is about 12968.4941300060. The cubic root of 168181840 is about 551.9838439576.

It can be divided in two parts, 1681 and 81840, that added together give a 4-th power (83521 = 17⁴).

The spelling of 168181840 in words is "one hundred sixty-eight million, one hundred eighty-one thousand, eight hundred forty".