209735430421 has 4 divisors (see below), whose sum is σ = 228802287744. Its totient is φ = 190668573100.

The previous prime is 209735430413. The next prime is 209735430529. The reversal of 209735430421 is 124034537902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 209735430421 - 2³ = 209735430413 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 (209735434421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9533428645 + ... + 9533428666.

It is an arithmetic number, because the mean of its divisors is an integer number (57200571936).

Almost surely, 2^209735430421 is an apocalyptic number.

It is an amenable number.

209735430421 is a deficient number, since it is larger than the sum of its proper divisors (19066857323).

209735430421 is a wasteful number, since it uses less digits than its factorization.

209735430421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19066857322.

The product of its (nonzero) digits is 181440, while the sum is 40.

The spelling of 209735430421 in words is "two hundred nine billion, seven hundred thirty-five million, four hundred thirty thousand, four hundred twenty-one".