40100821 has 4 divisors (see below), whose sum is σ = 40113792. Its totient is φ = 40087852.

The previous prime is 40100813. The next prime is 40100831. The reversal of 40100821 is 12800104.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 40100821 - 2³ = 40100813 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 40100795 and 40100804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40100831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1146 + ... + 9028.

It is an arithmetic number, because the mean of its divisors is an integer number (10028448).

Almost surely, 2^40100821 is an apocalyptic number.

It is an amenable number.

40100821 is a deficient number, since it is larger than the sum of its proper divisors (12971).

40100821 is an equidigital number, since it uses as much as digits as its factorization.

40100821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12970.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 40100821 is about 6332.5209040318. The cubic root of 40100821 is about 342.2822840687.

Adding to 40100821 its reverse (12800104), we get a palindrome (52900925).

The spelling of 40100821 in words is "forty million, one hundred thousand, eight hundred twenty-one".