400042493 has 2 divisors, whose sum is σ = 400042494. Its totient is φ = 400042492.

The previous prime is 400042481. The next prime is 400042523. The reversal of 400042493 is 394240004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 375855769 + 24186724 = 19387^2 + 4918^2 .

It is a cyclic number.

It is not a de Polignac number, because 400042493 - 2⁴ = 400042477 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400041493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200021246 + 200021247.

It is an arithmetic number, because the mean of its divisors is an integer number (200021247).

Almost surely, 2^400042493 is an apocalyptic number.

It is an amenable number.

400042493 is a deficient number, since it is larger than the sum of its proper divisors (1).

400042493 is an equidigital number, since it uses as much as digits as its factorization.

400042493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 400042493 is about 20001.0622967881. The cubic root of 400042493 is about 736.8323897293.

Adding to 400042493 its reverse (394240004), we get a palindrome (794282497).

The spelling of 400042493 in words is "four hundred million, forty-two thousand, four hundred ninety-three".