181264640 has 36 divisors (see below), whose sum is σ = 434188524. Its totient is φ = 72505344.

The previous prime is 181264637. The next prime is 181264661. The reversal of 181264640 is 46462181.

It can be written as a sum of positive squares in 2 ways, for example, as 71098624 + 110166016 = 8432^2 + 10496^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 181264597 and 181264606.

It is an unprimeable number.

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, 69527 + ... + 72086.

Almost surely, 2^181264640 is an apocalyptic number.

181264640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181264640 is an abundant number, since it is smaller than the sum of its proper divisors (252923884).

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

181264640 is an equidigital number, since it uses as much as digits as its factorization.

181264640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141634 (or 141620 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 181264640 is about 13463.4557228076. The cubic root of 181264640 is about 565.9408346301.

The spelling of 181264640 in words is "one hundred eighty-one million, two hundred sixty-four thousand, six hundred forty".