400543643 has 4 divisors (see below), whose sum is σ = 417958608. Its totient is φ = 383128680.

The previous prime is 400543639. The next prime is 400543669. The reversal of 400543643 is 346345004.

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

It is a cyclic number.

It is not a de Polignac number, because 400543643 - 2² = 400543639 is a prime.

It is a super-2 number, since 2×400543643² = 320870419895422898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400543603) 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, 8707448 + ... + 8707493.

It is an arithmetic number, because the mean of its divisors is an integer number (104489652).

Almost surely, 2^400543643 is an apocalyptic number.

400543643 is a deficient number, since it is larger than the sum of its proper divisors (17414965).

400543643 is a wasteful number, since it uses less digits than its factorization.

400543643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17414964.

The product of its (nonzero) digits is 17280, while the sum is 29.

The square root of 400543643 is about 20013.5864602025. The cubic root of 400543643 is about 737.1399482750.

Adding to 400543643 its reverse (346345004), we get a palindrome (746888647).

The spelling of 400543643 in words is "four hundred million, five hundred forty-three thousand, six hundred forty-three".