181225640 has 32 divisors (see below), whose sum is σ = 421821000. Its totient is φ = 69990144.

The previous prime is 181225637. The next prime is 181225657. The reversal of 181225640 is 46522181.

181225640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 95218564 + 86007076 = 9758^2 + 9274^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76955 + ... + 79274.

Almost surely, 2^181225640 is an apocalyptic number.

181225640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181225640 is an abundant number, since it is smaller than the sum of its proper divisors (240595360).

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

181225640 is a wasteful number, since it uses less digits than its factorization.

181225640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156269 (or 156265 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 181225640 is about 13462.0072797484. The cubic root of 181225640 is about 565.9002433788.

The spelling of 181225640 in words is "one hundred eighty-one million, two hundred twenty-five thousand, six hundred forty".