402440081 has 2 divisors, whose sum is σ = 402440082. Its totient is φ = 402440080.

The previous prime is 402440069. The next prime is 402440113. The reversal of 402440081 is 180044204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 402403600 + 36481 = 20060^2 + 191^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-402440081 is a prime.

It is a super-2 number, since 2×402440081² = 323916037590573122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (402440041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201220040 + 201220041.

It is an arithmetic number, because the mean of its divisors is an integer number (201220041).

Almost surely, 2^402440081 is an apocalyptic number.

It is an amenable number.

402440081 is a deficient number, since it is larger than the sum of its proper divisors (1).

402440081 is an equidigital number, since it uses as much as digits as its factorization.

402440081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1024, while the sum is 23.

The square root of 402440081 is about 20060.9092765009. The cubic root of 402440081 is about 738.3014860677.

Adding to 402440081 its reverse (180044204), we get a palindrome (582484285).

The spelling of 402440081 in words is "four hundred two million, four hundred forty thousand, eighty-one".