20871851417 has 2 divisors, whose sum is σ = 20871851418. Its totient is φ = 20871851416.

The previous prime is 20871851411. The next prime is 20871851447. The reversal of 20871851417 is 71415817802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20407836736 + 464014681 = 142856^2 + 21541^2 .

It is a cyclic number.

It is not a de Polignac number, because 20871851417 - 2¹⁰ = 20871850393 is a prime.

It is not a weakly prime, because it can be changed into another prime (20871851411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10435925708 + 10435925709.

It is an arithmetic number, because the mean of its divisors is an integer number (10435925709).

Almost surely, 2^20871851417 is an apocalyptic number.

It is an amenable number.

20871851417 is a deficient number, since it is larger than the sum of its proper divisors (1).

20871851417 is an equidigital number, since it uses as much as digits as its factorization.

20871851417 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 125440, while the sum is 44.

The spelling of 20871851417 in words is "twenty billion, eight hundred seventy-one million, eight hundred fifty-one thousand, four hundred seventeen".