21898217685 has 16 divisors (see below), whose sum is σ = 35292897216. Its totient is φ = 11593799808.

The previous prime is 21898217669. The next prime is 21898217699. The reversal of 21898217685 is 58671289812.

It is not a de Polignac number, because 21898217685 - 2⁴ = 21898217669 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5325979 + ... + 5330088.

It is an arithmetic number, because the mean of its divisors is an integer number (2205806076).

Almost surely, 2^21898217685 is an apocalyptic number.

It is an amenable number.

21898217685 is a deficient number, since it is larger than the sum of its proper divisors (13394679531).

21898217685 is a wasteful number, since it uses less digits than its factorization.

21898217685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10656212.

The product of its digits is 3870720, while the sum is 57.

The spelling of 21898217685 in words is "twenty-one billion, eight hundred ninety-eight million, two hundred seventeen thousand, six hundred eighty-five".