402116581 has 12 divisors (see below), whose sum is σ = 419386500. Its totient is φ = 385524608.

The previous prime is 402116573. The next prime is 402116609. The reversal of 402116581 is 185611204.

It can be written as a sum of positive squares in 6 ways, for example, as 10432900 + 391683681 = 3230^2 + 19791^2 .

It is not a de Polignac number, because 402116581 - 2³ = 402116573 is a prime.

It is a super-2 number, since 2×402116581² = 323395489430259122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402116501) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 123705 + ... + 126913.

It is an arithmetic number, because the mean of its divisors is an integer number (34948875).

Almost surely, 2^402116581 is an apocalyptic number.

It is an amenable number.

402116581 is a deficient number, since it is larger than the sum of its proper divisors (17269919).

402116581 is a wasteful number, since it uses less digits than its factorization.

402116581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3416 (or 3387 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 402116581 is about 20052.8447109132. The cubic root of 402116581 is about 738.1036060456.

Adding to 402116581 its reverse (185611204), we get a palindrome (587727785).

It can be divided in two parts, 4021 and 16581, that added together give a palindrome (20602).

The spelling of 402116581 in words is "four hundred two million, one hundred sixteen thousand, five hundred eighty-one".