400023521 has 4 divisors (see below), whose sum is σ = 417415872. Its totient is φ = 382631172.

The previous prime is 400023517. The next prime is 400023527. The reversal of 400023521 is 125320004.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 400023521 - 2² = 400023517 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 400023521.

It is not an unprimeable number, because it can be changed into a prime (400023527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8696141 + ... + 8696186.

It is an arithmetic number, because the mean of its divisors is an integer number (104353968).

Almost surely, 2^400023521 is an apocalyptic number.

It is an amenable number.

400023521 is a deficient number, since it is larger than the sum of its proper divisors (17392351).

400023521 is a wasteful number, since it uses less digits than its factorization.

400023521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17392350.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 400023521 is about 20000.5880163559. The cubic root of 400023521 is about 736.8207414625.

Adding to 400023521 its reverse (125320004), we get a palindrome (525343525).

The spelling of 400023521 in words is "four hundred million, twenty-three thousand, five hundred twenty-one".