20415681 has 48 divisors (see below), whose sum is σ = 35904960. Its totient is φ = 11007360.

The previous prime is 20415677. The next prime is 20415713. The reversal of 20415681 is 18651402.

It is not a de Polignac number, because 20415681 - 2² = 20415677 is a prime.

It is a super-2 number, since 2×20415681² = 833600061387522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20415611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 37050 + ... + 37596.

It is an arithmetic number, because the mean of its divisors is an integer number (748020).

Almost surely, 2^20415681 is an apocalyptic number.

It is an amenable number.

20415681 is a deficient number, since it is larger than the sum of its proper divisors (15489279).

20415681 is a wasteful number, since it uses less digits than its factorization.

20415681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606 (or 603 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 20415681 is about 4518.3714986707. The cubic root of 20415681 is about 273.3094345884.

The spelling of 20415681 in words is "twenty million, four hundred fifteen thousand, six hundred eighty-one".