402401621 has 2 divisors, whose sum is σ = 402401622. Its totient is φ = 402401620.

The previous prime is 402401609. The next prime is 402401647. The reversal of 402401621 is 126104204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 398441521 + 3960100 = 19961^2 + 1990^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-402401621 is a prime.

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 402401593 and 402401602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402401821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201200810 + 201200811.

It is an arithmetic number, because the mean of its divisors is an integer number (201200811).

Almost surely, 2^402401621 is an apocalyptic number.

It is an amenable number.

402401621 is a deficient number, since it is larger than the sum of its proper divisors (1).

402401621 is an equidigital number, since it uses as much as digits as its factorization.

402401621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 402401621 is about 20059.9506729204. The cubic root of 402401621 is about 738.2779662271.

Adding to 402401621 its reverse (126104204), we get a palindrome (528505825).

The spelling of 402401621 in words is "four hundred two million, four hundred one thousand, six hundred twenty-one".