400051821 has 16 divisors (see below), whose sum is σ = 604667840. Its totient is φ = 233228160.

The previous prime is 400051787. The next prime is 400051829. The reversal of 400051821 is 128150004.

It is not a de Polignac number, because 400051821 - 2⁷ = 400051693 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 (400051829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 269200 + ... + 270681.

It is an arithmetic number, because the mean of its divisors is an integer number (37791740).

Almost surely, 2^400051821 is an apocalyptic number.

It is an amenable number.

400051821 is a deficient number, since it is larger than the sum of its proper divisors (204616019).

400051821 is a wasteful number, since it uses less digits than its factorization.

400051821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539916.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 400051821 is about 20001.2954830431. The cubic root of 400051821 is about 736.8381167202.

The spelling of 400051821 in words is "four hundred million, fifty-one thousand, eight hundred twenty-one".