402021121 has 2 divisors, whose sum is σ = 402021122. Its totient is φ = 402021120.

The previous prime is 402021119. The next prime is 402021131. The reversal of 402021121 is 121120204.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 221414400 + 180606721 = 14880^2 + 13439^2 .

It is a cyclic number.

It is not a de Polignac number, because 402021121 - 2¹ = 402021119 is a prime.

Together with 402021119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (402021101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201010560 + 201010561.

It is an arithmetic number, because the mean of its divisors is an integer number (201010561).

Almost surely, 2^402021121 is an apocalyptic number.

It is an amenable number.

402021121 is a deficient number, since it is larger than the sum of its proper divisors (1).

402021121 is an equidigital number, since it uses as much as digits as its factorization.

402021121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 402021121 is about 20050.4643587125. The cubic root of 402021121 is about 738.0451943396.

Adding to 402021121 its reverse (121120204), we get a palindrome (523141325).

The spelling of 402021121 in words is "four hundred two million, twenty-one thousand, one hundred twenty-one".