400215823 has 16 divisors (see below), whose sum is σ = 463752000. Its totient is φ = 338291712.

The previous prime is 400215799. The next prime is 400215877. The reversal of 400215823 is 328512004.

It is a cyclic number.

It is not a de Polignac number, because 400215823 - 2⁹ = 400215311 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 (400215523) 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 15 ways as a sum of consecutive naturals, for example, 353923 + ... + 355051.

It is an arithmetic number, because the mean of its divisors is an integer number (28984500).

Almost surely, 2^400215823 is an apocalyptic number.

400215823 is a deficient number, since it is larger than the sum of its proper divisors (63536177).

400215823 is a wasteful number, since it uses less digits than its factorization.

400215823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1794.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 400215823 is about 20005.3948473905. The cubic root of 400215823 is about 736.9387923568.

Adding to 400215823 its reverse (328512004), we get a palindrome (728727827).

The spelling of 400215823 in words is "four hundred million, two hundred fifteen thousand, eight hundred twenty-three".