408919681 has 4 divisors (see below), whose sum is σ = 408975700. Its totient is φ = 408863664.

The previous prime is 408919673. The next prime is 408919703. The reversal of 408919681 is 186919804.

It is the 8256-th star number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 134189056 + 274730625 = 11584^2 + 16575^2 .

It is a cyclic number.

It is not a de Polignac number, because 408919681 - 2³ = 408919673 is a prime.

It is a super-2 number, since 2×408919681² = 334430611018283522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (408919081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15066 + ... + 32323.

It is an arithmetic number, because the mean of its divisors is an integer number (102243925).

Almost surely, 2^408919681 is an apocalyptic number.

It is an amenable number.

408919681 is a deficient number, since it is larger than the sum of its proper divisors (56019).

408919681 is an equidigital number, since it uses as much as digits as its factorization.

408919681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56018.

The product of its (nonzero) digits is 124416, while the sum is 46.

The square root of 408919681 is about 20221.7625591836. The cubic root of 408919681 is about 742.2428187208.

It can be divided in two parts, 408919 and 681, that added together give a square (409600 = 640²).

The spelling of 408919681 in words is "four hundred eight million, nine hundred nineteen thousand, six hundred eighty-one".