400402421 has 4 divisors (see below), whose sum is σ = 400618752. Its totient is φ = 400186092.

The previous prime is 400402403. The next prime is 400402459. The reversal of 400402421 is 124204004.

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 400402421 - 2¹⁸ = 400140277 is a prime.

It is a super-2 number, since 2×400402421² = 320644197485322482, which contains 22 as substring.

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 400402421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400402021) 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, 105365 + ... + 109098.

It is an arithmetic number, because the mean of its divisors is an integer number (100154688).

Almost surely, 2^400402421 is an apocalyptic number.

It is an amenable number.

400402421 is a deficient number, since it is larger than the sum of its proper divisors (216331).

400402421 is a wasteful number, since it uses less digits than its factorization.

400402421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216330.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 400402421 is about 20010.0579959180. The cubic root of 400402421 is about 737.0533055196.

Adding to 400402421 its reverse (124204004), we get a palindrome (524606425).

The spelling of 400402421 in words is "four hundred million, four hundred two thousand, four hundred twenty-one".