20494681 has 4 divisors (see below), whose sum is σ = 20507364. Its totient is φ = 20482000.

The previous prime is 20494667. The next prime is 20494699. The reversal of 20494681 is 18649402.

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 3553225 + 16941456 = 1885^2 + 4116^2 .

It is a cyclic number.

It is not a de Polignac number, because 20494681 - 2⁷ = 20494553 is a prime.

It is a super-2 number, since 2×20494681² = 840063898583522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20494601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3490 + ... + 7291.

It is an arithmetic number, because the mean of its divisors is an integer number (5126841).

Almost surely, 2^20494681 is an apocalyptic number.

It is an amenable number.

20494681 is a deficient number, since it is larger than the sum of its proper divisors (12683).

20494681 is a wasteful number, since it uses less digits than its factorization.

20494681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12682.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 20494681 is about 4527.1051456753. The cubic root of 20494681 is about 273.6615112617.

The spelling of 20494681 in words is "twenty million, four hundred ninety-four thousand, six hundred eighty-one".