217609689421 has 16 divisors (see below), whose sum is σ = 223725237120. Its totient is φ = 211603492800.

The previous prime is 217609689419. The next prime is 217609689443. The reversal of 217609689421 is 124986906712.

It is a cyclic number.

It is not a de Polignac number, because 217609689421 - 2¹ = 217609689419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217609669421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1286451 + ... + 1445743.

It is an arithmetic number, because the mean of its divisors is an integer number (13982827320).

Almost surely, 2^217609689421 is an apocalyptic number.

It is an amenable number.

217609689421 is a deficient number, since it is larger than the sum of its proper divisors (6115547699).

217609689421 is a wasteful number, since it uses less digits than its factorization.

217609689421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159636.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 217609689421 in words is "two hundred seventeen billion, six hundred nine million, six hundred eighty-nine thousand, four hundred twenty-one".