21800871457 has 4 divisors (see below), whose sum is σ = 21801804676. Its totient is φ = 21799938240.

The previous prime is 21800871431. The next prime is 21800871461. The reversal of 21800871457 is 75417800812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6183620496 + 15617250961 = 78636^2 + 124969^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21800871457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21800871487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 430644 + ... + 478597.

It is an arithmetic number, because the mean of its divisors is an integer number (5450451169).

Almost surely, 2^21800871457 is an apocalyptic number.

It is an amenable number.

21800871457 is a deficient number, since it is larger than the sum of its proper divisors (933219).

21800871457 is an equidigital number, since it uses as much as digits as its factorization.

21800871457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 933218.

The product of its (nonzero) digits is 125440, while the sum is 43.

The spelling of 21800871457 in words is "twenty-one billion, eight hundred million, eight hundred seventy-one thousand, four hundred fifty-seven".