20213421 has 4 divisors (see below), whose sum is σ = 26951232. Its totient is φ = 13475612.

The previous prime is 20213419. The next prime is 20213437. The reversal of 20213421 is 12431202.

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 20213421 - 2¹ = 20213419 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20213421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20213411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3368901 + ... + 3368906.

It is an arithmetic number, because the mean of its divisors is an integer number (6737808).

Almost surely, 2^20213421 is an apocalyptic number.

It is an amenable number.

20213421 is a deficient number, since it is larger than the sum of its proper divisors (6737811).

20213421 is an equidigital number, since it uses as much as digits as its factorization.

20213421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6737810.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 20213421 is about 4495.9338295842. The cubic root of 20213421 is about 272.4038703653.

Adding to 20213421 its reverse (12431202), we get a palindrome (32644623).

The spelling of 20213421 in words is "twenty million, two hundred thirteen thousand, four hundred twenty-one".