40821691 has 4 divisors (see below), whose sum is σ = 41817384. Its totient is φ = 39826000.

The previous prime is 40821667. The next prime is 40821701. The reversal of 40821691 is 19612804.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 40821691 - 2⁷ = 40821563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40821611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 497785 + ... + 497866.

It is an arithmetic number, because the mean of its divisors is an integer number (10454346).

Almost surely, 2^40821691 is an apocalyptic number.

40821691 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

40821691 is a deficient number, since it is larger than the sum of its proper divisors (995693).

40821691 is an equidigital number, since it uses as much as digits as its factorization.

40821691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995692.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 40821691 is about 6389.1854723431. The cubic root of 40821691 is about 344.3211210687.

The spelling of 40821691 in words is "forty million, eight hundred twenty-one thousand, six hundred ninety-one".