400405501 has 4 divisors (see below), whose sum is σ = 400675900. Its totient is φ = 400135104.

The previous prime is 400405463. The next prime is 400405507. The reversal of 400405501 is 105504004.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 28879876 + 371525625 = 5374^2 + 19275^2 .

It is a cyclic number.

It is not a de Polignac number, because 400405501 - 2¹⁵ = 400372733 is a prime.

It is a super-2 number, since 2×400405501² = 320649130462122002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400405507) 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, 132966 + ... + 135943.

It is an arithmetic number, because the mean of its divisors is an integer number (100168975).

Almost surely, 2^400405501 is an apocalyptic number.

It is an amenable number.

400405501 is a deficient number, since it is larger than the sum of its proper divisors (270399).

400405501 is a wasteful number, since it uses less digits than its factorization.

400405501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270398.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 400405501 is about 20010.1349570661. The cubic root of 400405501 is about 737.0551953836.

Adding to 400405501 its reverse (105504004), we get a palindrome (505909505).

The spelling of 400405501 in words is "four hundred million, four hundred five thousand, five hundred one".