40020400021 has 12 divisors (see below), whose sum is σ = 47007172128. Its totient is φ = 33376078512.

The previous prime is 40020399983. The next prime is 40020400051. The reversal of 40020400021 is 12000402004.

It is not a de Polignac number, because 40020400021 - 2²⁷ = 39886182293 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 40020399974 and 40020400010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40020400051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2078511 + ... + 2097676.

It is an arithmetic number, because the mean of its divisors is an integer number (3917264344).

Almost surely, 2^40020400021 is an apocalyptic number.

It is an amenable number.

40020400021 is a deficient number, since it is larger than the sum of its proper divisors (6986772107).

40020400021 is an equidigital number, since it uses as much as digits as its factorization.

40020400021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4176268 (or 4176231 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 13.

Adding to 40020400021 its reverse (12000402004), we get a palindrome (52020802025).

The spelling of 40020400021 in words is "forty billion, twenty million, four hundred thousand, twenty-one".