400039643 has 4 divisors (see below), whose sum is σ = 400081200. Its totient is φ = 399998088.

The previous prime is 400039613. The next prime is 400039657. The reversal of 400039643 is 346930004.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 400039643 - 2²² = 395845339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400039613) 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, 1946 + ... + 28352.

It is an arithmetic number, because the mean of its divisors is an integer number (100020300).

Almost surely, 2^400039643 is an apocalyptic number.

400039643 is a deficient number, since it is larger than the sum of its proper divisors (41557).

400039643 is a wasteful number, since it uses less digits than its factorization.

400039643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41556.

The product of its (nonzero) digits is 7776, while the sum is 29.

The square root of 400039643 is about 20000.9910504455. The cubic root of 400039643 is about 736.8306399341.

Adding to 400039643 its reverse (346930004), we get a palindrome (746969647).

The spelling of 400039643 in words is "four hundred million, thirty-nine thousand, six hundred forty-three".