181211940 has 432 divisors, whose sum is σ = 729001728. Its totient is φ = 35582976.

The previous prime is 181211893. The next prime is 181211971. The reversal of 181211940 is 49112181.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4897602 + ... + 4897638.

It is an arithmetic number, because the mean of its divisors is an integer number (1687504).

Almost surely, 2^181211940 is an apocalyptic number.

181211940 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 181211940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (364500864).

181211940 is an abundant number, since it is smaller than the sum of its proper divisors (547789788).

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

181211940 is a wasteful number, since it uses less digits than its factorization.

181211940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 181211940 is about 13461.4984307097. The cubic root of 181211940 is about 565.8859830186.

The spelling of 181211940 in words is "one hundred eighty-one million, two hundred eleven thousand, nine hundred forty".