400039861 has 8 divisors (see below), whose sum is σ = 431164440. Its totient is φ = 368965632.

The previous prime is 400039847. The next prime is 400039867. The reversal of 400039861 is 168930004.

It can be written as a sum of positive squares in 4 ways, for example, as 9186961 + 390852900 = 3031^2 + 19770^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400039861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400039867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4821 + ... + 28693.

It is an arithmetic number, because the mean of its divisors is an integer number (53895555).

Almost surely, 2^400039861 is an apocalyptic number.

It is an amenable number.

400039861 is a deficient number, since it is larger than the sum of its proper divisors (31124579).

400039861 is a wasteful number, since it uses less digits than its factorization.

400039861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25175.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 400039861 is about 20000.9965001747. The cubic root of 400039861 is about 736.8307737784.

Adding to 400039861 its reverse (168930004), we get a palindrome (568969865).

The spelling of 400039861 in words is "four hundred million, thirty-nine thousand, eight hundred sixty-one".