21898538819 has 4 divisors (see below), whose sum is σ = 22111146096. Its totient is φ = 21685931544.

The previous prime is 21898538773. The next prime is 21898538833. The reversal of 21898538819 is 91883589812.

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

It is a cyclic number.

It is not a de Polignac number, because 21898538819 - 2¹⁶ = 21898473283 is a prime.

It is a super-2 number, since 2×21898538819² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21898538719) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106303484 + ... + 106303689.

It is an arithmetic number, because the mean of its divisors is an integer number (5527786524).

Almost surely, 2^21898538819 is an apocalyptic number.

21898538819 is a deficient number, since it is larger than the sum of its proper divisors (212607277).

21898538819 is a wasteful number, since it uses less digits than its factorization.

21898538819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212607276.

The product of its digits is 9953280, while the sum is 62.

The spelling of 21898538819 in words is "twenty-one billion, eight hundred ninety-eight million, five hundred thirty-eight thousand, eight hundred nineteen".