400684021 has 8 divisors (see below), whose sum is σ = 423698688. Its totient is φ = 378300000.

The previous prime is 400684007. The next prime is 400684043. The reversal of 400684021 is 120486004.

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 400684021 - 2⁷ = 400683893 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 (400684001) 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, 156355 + ... + 158896.

It is an arithmetic number, because the mean of its divisors is an integer number (52962336).

Almost surely, 2^400684021 is an apocalyptic number.

400684021 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

It is an amenable number.

400684021 is a deficient number, since it is larger than the sum of its proper divisors (23014667).

400684021 is a wasteful number, since it uses less digits than its factorization.

400684021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315323.

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 400684021 is about 20017.0932205453. The cubic root of 400684021 is about 737.2260530371.

The spelling of 400684021 in words is "four hundred million, six hundred eighty-four thousand, twenty-one".