21535217898 has 16 divisors (see below), whose sum is σ = 43883086176. Its totient is φ = 7042964240.

The previous prime is 21535217843. The next prime is 21535217917. The reversal of 21535217898 is 89871253512.

It is a self number, because there is not a number n which added to its sum of digits gives 21535217898.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33860088 + ... + 33860723.

It is an arithmetic number, because the mean of its divisors is an integer number (2742692886).

Almost surely, 2^21535217898 is an apocalyptic number.

21535217898 is an abundant number, since it is smaller than the sum of its proper divisors (22347868278).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21535217898 is a wasteful number, since it uses less digits than its factorization.

21535217898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67720869.

The product of its digits is 1209600, while the sum is 51.

The spelling of 21535217898 in words is "twenty-one billion, five hundred thirty-five million, two hundred seventeen thousand, eight hundred ninety-eight".