20604557581 has 8 divisors (see below), whose sum is σ = 21691309280. Its totient is φ = 19518036048.

The previous prime is 20604557579. The next prime is 20604557639. The reversal of 20604557581 is 18575540602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20604557581 - 2¹ = 20604557579 is a prime.

It is a super-2 number, since 2×20604557581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20604557531) 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 7 ways as a sum of consecutive naturals, for example, 144430 + ... + 249136.

It is an arithmetic number, because the mean of its divisors is an integer number (2711413660).

Almost surely, 2^20604557581 is an apocalyptic number.

It is an amenable number.

20604557581 is a deficient number, since it is larger than the sum of its proper divisors (1086751699).

20604557581 is a wasteful number, since it uses less digits than its factorization.

20604557581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115083.

The product of its (nonzero) digits is 336000, while the sum is 43.

The spelling of 20604557581 in words is "twenty billion, six hundred four million, five hundred fifty-seven thousand, five hundred eighty-one".