20581616 has 30 divisors (see below), whose sum is σ = 43835736. Its totient is φ = 9354400.

The previous prime is 20581609. The next prime is 20581643. The reversal of 20581616 is 61618502.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 3380 + ... + 7251.

Almost surely, 2^20581616 is an apocalyptic number.

It is an amenable number.

20581616 is an abundant number, since it is smaller than the sum of its proper divisors (23254120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20581616 is a wasteful number, since it uses less digits than its factorization.

20581616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10661 (or 10644 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 20581616 is about 4536.6965955417. The cubic root of 20581616 is about 274.0479075128.

The spelling of 20581616 in words is "twenty million, five hundred eighty-one thousand, six hundred sixteen".