20811505275 has 36 divisors (see below), whose sum is σ = 40664424840. Its totient is φ = 10090425600.

The previous prime is 20811505271. The next prime is 20811505291. The reversal of 20811505275 is 57250511802.

20811505275 is a `hidden beast` number, since 2 + 0 + 81 + 1 + 50 + 527 + 5 = 666.

It is not a de Polignac number, because 20811505275 - 2² = 20811505271 is a prime.

It is a super-2 number, since 2×20811505275² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20811505271) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4201870 + ... + 4206819.

Almost surely, 2^20811505275 is an apocalyptic number.

20811505275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20811505275 is a deficient number, since it is larger than the sum of its proper divisors (19852919565).

20811505275 is a wasteful number, since it uses less digits than its factorization.

20811505275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8408716 (or 8408708 counting only the distinct ones).

The product of its (nonzero) digits is 28000, while the sum is 36.

The spelling of 20811505275 in words is "twenty billion, eight hundred eleven million, five hundred five thousand, two hundred seventy-five".