402040421 has 2 divisors, whose sum is σ = 402040422. Its totient is φ = 402040420.

The previous prime is 402040417. The next prime is 402040439. The reversal of 402040421 is 124040204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 365001025 + 37039396 = 19105^2 + 6086^2 .

It is a cyclic number.

It is not a de Polignac number, because 402040421 - 2² = 402040417 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 402040421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402040321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201020210 + 201020211.

It is an arithmetic number, because the mean of its divisors is an integer number (201020211).

Almost surely, 2^402040421 is an apocalyptic number.

It is an amenable number.

402040421 is a deficient number, since it is larger than the sum of its proper divisors (1).

402040421 is an equidigital number, since it uses as much as digits as its factorization.

402040421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 402040421 is about 20050.9456385478. The cubic root of 402040421 is about 738.0570047011.

Adding to 402040421 its reverse (124040204), we get a palindrome (526080625).

The spelling of 402040421 in words is "four hundred two million, forty thousand, four hundred twenty-one".