20811625158581 has 16 divisors (see below), whose sum is σ = 21781391344128. Its totient is φ = 19860615244800.

The previous prime is 20811625158529. The next prime is 20811625158617. The reversal of 20811625158581 is 18585152611802.

It is a cyclic number.

It is not a de Polignac number, because 20811625158581 - 2⁶ = 20811625158517 is a prime.

It is a super-2 number, since 2×20811625158581² (a number of 27 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 (20811625154581) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11080190 + ... + 12821616.

It is an arithmetic number, because the mean of its divisors is an integer number (1361336959008).

Almost surely, 2^{20811625158581} is an apocalyptic number.

It is an amenable number.

20811625158581 is a deficient number, since it is larger than the sum of its proper divisors (969766185547).

20811625158581 is a wasteful number, since it uses less digits than its factorization.

20811625158581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1746812.

The product of its (nonzero) digits is 1536000, while the sum is 53.

The spelling of 20811625158581 in words is "twenty trillion, eight hundred eleven billion, six hundred twenty-five million, one hundred fifty-eight thousand, five hundred eighty-one".