400055821 has 8 divisors (see below), whose sum is σ = 440288064. Its totient is φ = 360467520.

The previous prime is 400055809. The next prime is 400055827. The reversal of 400055821 is 128550004.

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 400055821 - 2¹³ = 400047629 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 (400055827) 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, 159681 + ... + 162166.

It is an arithmetic number, because the mean of its divisors is an integer number (55036008).

Almost surely, 2^400055821 is an apocalyptic number.

It is an amenable number.

400055821 is a deficient number, since it is larger than the sum of its proper divisors (40232243).

400055821 is a wasteful number, since it uses less digits than its factorization.

400055821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321971.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 400055821 is about 20001.3954763161. The cubic root of 400055821 is about 736.8405725209.

The spelling of 400055821 in words is "four hundred million, fifty-five thousand, eight hundred twenty-one".