402442421 has 2 divisors, whose sum is σ = 402442422. Its totient is φ = 402442420.

The previous prime is 402442393. The next prime is 402442423. The reversal of 402442421 is 124244204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205348900 + 197093521 = 14330^2 + 14039^2 .

It is a cyclic number.

It is not a de Polignac number, because 402442421 - 2²² = 398248117 is a prime.

Together with 402442423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402442423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201221210 + 201221211.

It is an arithmetic number, because the mean of its divisors is an integer number (201221211).

Almost surely, 2^402442421 is an apocalyptic number.

It is an amenable number.

402442421 is a deficient number, since it is larger than the sum of its proper divisors (1).

402442421 is an equidigital number, since it uses as much as digits as its factorization.

402442421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2048, while the sum is 23.

The square root of 402442421 is about 20060.9675987974. The cubic root of 402442421 is about 738.3029170237.

Adding to 402442421 its reverse (124244204), we get a palindrome (526686625).

The spelling of 402442421 in words is "four hundred two million, four hundred forty-two thousand, four hundred twenty-one".