20543312691 has 16 divisors (see below), whose sum is σ = 33201313920. Its totient is φ = 12450492360.

The previous prime is 20543312689. The next prime is 20543312723. The reversal of 20543312691 is 19621334502.

20543312691 is a `hidden beast` number, since 2 + 0 + 543 + 3 + 1 + 26 + 91 = 666.

It is not a de Polignac number, because 20543312691 - 2¹ = 20543312689 is a prime.

It is a super-2 number, since 2×20543312691² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20543312191) 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, 34584405 + ... + 34584998.

It is an arithmetic number, because the mean of its divisors is an integer number (2075082120).

Almost surely, 2^20543312691 is an apocalyptic number.

20543312691 is a deficient number, since it is larger than the sum of its proper divisors (12658001229).

20543312691 is a wasteful number, since it uses less digits than its factorization.

20543312691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69169423 (or 69169417 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The spelling of 20543312691 in words is "twenty billion, five hundred forty-three million, three hundred twelve thousand, six hundred ninety-one".