40991820 has 48 divisors (see below), whose sum is σ = 115492608. Its totient is φ = 10863040.

The previous prime is 40991809. The next prime is 40991861. The reversal of 40991820 is 2819904.

40991820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7975 + ... + 12065.

It is an arithmetic number, because the mean of its divisors is an integer number (2406096).

Almost surely, 2^40991820 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 40991820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (57746304).

40991820 is an abundant number, since it is smaller than the sum of its proper divisors (74500788).

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

40991820 is a wasteful number, since it uses less digits than its factorization.

40991820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4270 (or 4268 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 40991820 is about 6402.4854548839. The cubic root of 40991820 is about 344.7987904667.

It can be divided in two parts, 409 and 91820, that added together give a palindrome (92229).

The spelling of 40991820 in words is "forty million, nine hundred ninety-one thousand, eight hundred twenty".