400121021 has 8 divisors (see below), whose sum is σ = 407069184. Its totient is φ = 393185520.

The previous prime is 400121003. The next prime is 400121039. The reversal of 400121021 is 120121004.

It is an interprime number because it is at equal distance from previous prime (400121003) and next prime (400121039).

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

It is a cyclic number.

It is not a de Polignac number, because 400121021 - 2¹⁰ = 400119997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400120993 and 400121011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400123021) 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 7 ways as a sum of consecutive naturals, for example, 78476 + ... + 83418.

It is an arithmetic number, because the mean of its divisors is an integer number (50883648).

Almost surely, 2^400121021 is an apocalyptic number.

It is an amenable number.

400121021 is a deficient number, since it is larger than the sum of its proper divisors (6948163).

400121021 is a wasteful number, since it uses less digits than its factorization.

400121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6331.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 400121021 is about 20003.0252961896. The cubic root of 400121021 is about 736.8805997647.

Adding to 400121021 its reverse (120121004), we get a palindrome (520242025).

The spelling of 400121021 in words is "four hundred million, one hundred twenty-one thousand, twenty-one".