20117421 has 24 divisors (see below), whose sum is σ = 29995680. Its totient is φ = 12985056.

The previous prime is 20117411. The next prime is 20117431. The reversal of 20117421 is 12471102.

It is an interprime number because it is at equal distance from previous prime (20117411) and next prime (20117431).

It is not a de Polignac number, because 20117421 - 2⁹ = 20116909 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20117394 and 20117403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20117401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 87735 + ... + 87963.

It is an arithmetic number, because the mean of its divisors is an integer number (1249820).

Almost surely, 2^20117421 is an apocalyptic number.

It is an amenable number.

20117421 is a deficient number, since it is larger than the sum of its proper divisors (9878259).

20117421 is a wasteful number, since it uses less digits than its factorization.

20117421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505 (or 502 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 20117421 is about 4485.2448093722. The cubic root of 20117421 is about 271.9719414901.

Adding to 20117421 its reverse (12471102), we get a palindrome (32588523).

The spelling of 20117421 in words is "twenty million, one hundred seventeen thousand, four hundred twenty-one".