40028821 has 4 divisors (see below), whose sum is σ = 45747232. Its totient is φ = 34310412.

The previous prime is 40028789. The next prime is 40028827. The reversal of 40028821 is 12882004.

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.

It is a cyclic number.

It is not a de Polignac number, because 40028821 - 2⁵ = 40028789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40028827) 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, 2859195 + ... + 2859208.

It is an arithmetic number, because the mean of its divisors is an integer number (11436808).

Almost surely, 2^40028821 is an apocalyptic number.

It is an amenable number.

40028821 is a deficient number, since it is larger than the sum of its proper divisors (5718411).

40028821 is an equidigital number, since it uses as much as digits as its factorization.

40028821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5718410.

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 40028821 is about 6326.8334101666. The cubic root of 40028821 is about 342.0773083102.

It can be divided in two parts, 400288 and 21, that multiplied together give a palindrome (8406048).

The spelling of 40028821 in words is "forty million, twenty-eight thousand, eight hundred twenty-one".