20811809252473 has 16 divisors (see below), whose sum is σ = 21475742058496. Its totient is φ = 20156238184320.

The previous prime is 20811809252467. The next prime is 20811809252501. The reversal of 20811809252473 is 37425290811802.

It is a cyclic number.

It is not a de Polignac number, because 20811809252473 - 2²⁵ = 20811775698041 is a prime.

It is a super-2 number, since 2×20811809252473² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20811809252473.

It is not an unprimeable number, because it can be changed into a prime (20811809256473) 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, 8486143 + ... + 10660123.

It is an arithmetic number, because the mean of its divisors is an integer number (1342233878656).

Almost surely, 2^{20811809252473} is an apocalyptic number.

It is an amenable number.

20811809252473 is a deficient number, since it is larger than the sum of its proper divisors (663932806023).

20811809252473 is a wasteful number, since it uses less digits than its factorization.

20811809252473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2175904.

The product of its (nonzero) digits is 1935360, while the sum is 52.

The spelling of 20811809252473 in words is "twenty trillion, eight hundred eleven billion, eight hundred nine million, two hundred fifty-two thousand, four hundred seventy-three".