20416581 has 12 divisors (see below), whose sum is σ = 29572608. Its totient is φ = 13573224.

The previous prime is 20416549. The next prime is 20416597. The reversal of 20416581 is 18561402.

20416581 is a `hidden beast` number, since 2 + 0 + 4 + 1 + 658 + 1 = 666.

It is not a de Polignac number, because 20416581 - 2⁵ = 20416549 is a prime.

It is a super-2 number, since 2×20416581² = 833673559459122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20416381) 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 11 ways as a sum of consecutive naturals, for example, 486 + ... + 6408.

It is an arithmetic number, because the mean of its divisors is an integer number (2464384).

Almost surely, 2^20416581 is an apocalyptic number.

It is an amenable number.

20416581 is a deficient number, since it is larger than the sum of its proper divisors (9156027).

20416581 is a wasteful number, since it uses less digits than its factorization.

20416581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6312 (or 6309 counting only the distinct ones).

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

The square root of 20416581 is about 4518.4710909776. The cubic root of 20416581 is about 273.3134506986.

Adding to 20416581 its reverse (18561402), we get a palindrome (38977983).

The spelling of 20416581 in words is "twenty million, four hundred sixteen thousand, five hundred eighty-one".