402021331 has 2 divisors, whose sum is σ = 402021332. Its totient is φ = 402021330.

The previous prime is 402021329. The next prime is 402021353. The reversal of 402021331 is 133120204.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 402021331 - 2¹ = 402021329 is a prime.

It is a super-2 number, since 2×402021331² = 323242301158023122, which contains 22 as substring.

Together with 402021329, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (402021131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201010665 + 201010666.

It is an arithmetic number, because the mean of its divisors is an integer number (201010666).

Almost surely, 2^402021331 is an apocalyptic number.

402021331 is a deficient number, since it is larger than the sum of its proper divisors (1).

402021331 is an equidigital number, since it uses as much as digits as its factorization.

402021331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 402021331 is about 20050.4695954983. The cubic root of 402021331 is about 738.0453228482.

Adding to 402021331 its reverse (133120204), we get a palindrome (535141535).

The spelling of 402021331 in words is "four hundred two million, twenty-one thousand, three hundred thirty-one".