20421270917 has 8 divisors (see below), whose sum is σ = 21031632000. Its totient is φ = 19813985424.

The previous prime is 20421270899. The next prime is 20421270923. The reversal of 20421270917 is 71907212402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20421270917 - 2¹⁰ = 20421269893 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 (20421270977) 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 7 ways as a sum of consecutive naturals, for example, 755417 + ... + 781982.

It is an arithmetic number, because the mean of its divisors is an integer number (2628954000).

Almost surely, 2^20421270917 is an apocalyptic number.

It is an amenable number.

20421270917 is a deficient number, since it is larger than the sum of its proper divisors (610361083).

20421270917 is a wasteful number, since it uses less digits than its factorization.

20421270917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1537795.

The product of its (nonzero) digits is 14112, while the sum is 35.

The spelling of 20421270917 in words is "twenty billion, four hundred twenty-one million, two hundred seventy thousand, nine hundred seventeen".