400012021 has 8 divisors (see below), whose sum is σ = 417628800. Its totient is φ = 382414032.

The previous prime is 400012007. The next prime is 400012033. The reversal of 400012021 is 120210004.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400012021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400011989 and 400012007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400012061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55216 + ... + 62038.

It is an arithmetic number, because the mean of its divisors is an integer number (52203600).

Almost surely, 2^400012021 is an apocalyptic number.

It is an amenable number.

400012021 is a deficient number, since it is larger than the sum of its proper divisors (17616779).

400012021 is a wasteful number, since it uses less digits than its factorization.

400012021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9395.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 400012021 is about 20000.3005227422. The cubic root of 400012021 is about 736.8136806112.

Adding to 400012021 its reverse (120210004), we get a palindrome (520222025).

The spelling of 400012021 in words is "four hundred million, twelve thousand, twenty-one".