20871851447 has 2 divisors, whose sum is σ = 20871851448. Its totient is φ = 20871851446.

The previous prime is 20871851417. The next prime is 20871851471. The reversal of 20871851447 is 74415817802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20871851447 - 2⁶ = 20871851383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20871851417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10435925723 + 10435925724.

It is an arithmetic number, because the mean of its divisors is an integer number (10435925724).

Almost surely, 2^20871851447 is an apocalyptic number.

20871851447 is a deficient number, since it is larger than the sum of its proper divisors (1).

20871851447 is an equidigital number, since it uses as much as digits as its factorization.

20871851447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 501760, while the sum is 47.

The spelling of 20871851447 in words is "twenty billion, eight hundred seventy-one million, eight hundred fifty-one thousand, four hundred forty-seven".