181394640 has 480 divisors, whose sum is σ = 762617856. Its totient is φ = 39191040.

The previous prime is 181394621. The next prime is 181394651. The reversal of 181394640 is 46493181.

181394640 is a `hidden beast` number, since 1 + 8 + 1 + 3 + 9 + 4 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 181394595 and 181394604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4218459 + ... + 4218501.

Almost surely, 2^181394640 is an apocalyptic number.

181394640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181394640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (381308928).

181394640 is an abundant number, since it is smaller than the sum of its proper divisors (581223216).

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

181394640 is a wasteful number, since it uses less digits than its factorization.

181394640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 181394640 is about 13468.2827413149. The cubic root of 181394640 is about 566.0760967662.

The spelling of 181394640 in words is "one hundred eighty-one million, three hundred ninety-four thousand, six hundred forty".