400342121 has 2 divisors, whose sum is σ = 400342122. Its totient is φ = 400342120.

The previous prime is 400342093. The next prime is 400342123. The reversal of 400342121 is 121243004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 229674025 + 170668096 = 15155^2 + 13064^2 .

It is a cyclic number.

It is not a de Polignac number, because 400342121 - 2⁶ = 400342057 is a prime.

Together with 400342123, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 400342121.

It is not a weakly prime, because it can be changed into another prime (400342123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200171060 + 200171061.

It is an arithmetic number, because the mean of its divisors is an integer number (200171061).

Almost surely, 2^400342121 is an apocalyptic number.

It is an amenable number.

400342121 is a deficient number, since it is larger than the sum of its proper divisors (1).

400342121 is an equidigital number, since it uses as much as digits as its factorization.

400342121 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 400342121 is about 20008.5511969258. The cubic root of 400342121 is about 737.0163039571.

Adding to 400342121 its reverse (121243004), we get a palindrome (521585125).

The spelling of 400342121 in words is "four hundred million, three hundred forty-two thousand, one hundred twenty-one".