40181820 has 96 divisors (see below), whose sum is σ = 133056000. Its totient is φ = 8865024.

The previous prime is 40181803. The next prime is 40181821. The reversal of 40181820 is 2818104.

It is a super-2 number, since 2×40181820² = 3229157317024800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40181821) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10531 + ... + 13829.

It is an arithmetic number, because the mean of its divisors is an integer number (1386000).

Almost surely, 2^40181820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 40181820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66528000).

40181820 is an abundant number, since it is smaller than the sum of its proper divisors (92874180).

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

40181820 is a wasteful number, since it uses less digits than its factorization.

40181820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3347 (or 3345 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 40181820 is about 6338.9131560544. The cubic root of 40181820 is about 342.5125858944.

Adding to 40181820 its reverse (2818104), we get a palindrome (42999924).

The spelling of 40181820 in words is "forty million, one hundred eighty-one thousand, eight hundred twenty".