21205598871 has 8 divisors (see below), whose sum is σ = 28524345840. Its totient is φ = 14011958912.

The previous prime is 21205598861. The next prime is 21205598881. The reversal of 21205598871 is 17889550212.

It is an interprime number because it is at equal distance from previous prime (21205598861) and next prime (21205598881).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21205598871 - 2¹¹ = 21205596823 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21205598871.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21205598861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31276356 + ... + 31277033.

It is an arithmetic number, because the mean of its divisors is an integer number (3565543230).

Almost surely, 2^21205598871 is an apocalyptic number.

21205598871 is a deficient number, since it is larger than the sum of its proper divisors (7318746969).

21205598871 is a wasteful number, since it uses less digits than its factorization.

21205598871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62553505.

The product of its (nonzero) digits is 403200, while the sum is 48.

The spelling of 21205598871 in words is "twenty-one billion, two hundred five million, five hundred ninety-eight thousand, eight hundred seventy-one".