400042061 has 2 divisors, whose sum is σ = 400042062. Its totient is φ = 400042060.

The previous prime is 400042031. The next prime is 400042063. The reversal of 400042061 is 160240004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 225300100 + 174741961 = 15010^2 + 13219^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400042061 is a prime.

It is a Sophie Germain prime.

Together with 400042063, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400042063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200021030 + 200021031.

It is an arithmetic number, because the mean of its divisors is an integer number (200021031).

Almost surely, 2^400042061 is an apocalyptic number.

It is an amenable number.

400042061 is a deficient number, since it is larger than the sum of its proper divisors (1).

400042061 is an equidigital number, since it uses as much as digits as its factorization.

400042061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 400042061 is about 20001.0514973588. The cubic root of 400042061 is about 736.8321244977.

Adding to 400042061 its reverse (160240004), we get a palindrome (560282065).

The spelling of 400042061 in words is "four hundred million, forty-two thousand, sixty-one".