40105821 has 8 divisors (see below), whose sum is σ = 61113664. Its totient is φ = 22917600.

The previous prime is 40105801. The next prime is 40105823. The reversal of 40105821 is 12850104.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 40105821 - 2⁶ = 40105757 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1909801 = 40105821 / (4 + 0 + 1 + 0 + 5 + 8 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40105823) 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 7 ways as a sum of consecutive naturals, for example, 954880 + ... + 954921.

It is an arithmetic number, because the mean of its divisors is an integer number (7639208).

Almost surely, 2^40105821 is an apocalyptic number.

It is an amenable number.

40105821 is a deficient number, since it is larger than the sum of its proper divisors (21007843).

40105821 is a wasteful number, since it uses less digits than its factorization.

40105821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1909811.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 40105821 is about 6332.9156792113. The cubic root of 40105821 is about 342.2965093825.

Adding to 40105821 its reverse (12850104), we get a palindrome (52955925).

The spelling of 40105821 in words is "forty million, one hundred five thousand, eight hundred twenty-one".