20681891343 has 36 divisors (see below), whose sum is σ = 32568118440. Its totient is φ = 12611737152.

The previous prime is 20681891317. The next prime is 20681891357. The reversal of 20681891343 is 34319818602.

20681891343 is a `hidden beast` number, since 206 + 8 + 18 + 91 + 343 = 666.

It is a Cunningham number, because it is equal to 143812²-1.

It is not a de Polignac number, because 20681891343 - 2¹⁶ = 20681825807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20681891303) 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, 71905 + ... + 215717.

Almost surely, 2^20681891343 is an apocalyptic number.

20681891343 is a deficient number, since it is larger than the sum of its proper divisors (11886227097).

20681891343 is a wasteful number, since it uses less digits than its factorization.

20681891343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143896 (or 143864 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 20681891343 in words is "twenty billion, six hundred eighty-one million, eight hundred ninety-one thousand, three hundred forty-three".