20421236 has 12 divisors (see below), whose sum is σ = 38986080. Its totient is φ = 9282360.

The previous prime is 20421229. The next prime is 20421241. The reversal of 20421236 is 63212402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 232016 + ... + 232103.

It is an arithmetic number, because the mean of its divisors is an integer number (3248840).

Almost surely, 2^20421236 is an apocalyptic number.

It is an amenable number.

20421236 is a deficient number, since it is larger than the sum of its proper divisors (18564844).

20421236 is a wasteful number, since it uses less digits than its factorization.

20421236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 464134 (or 464132 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 20421236 is about 4518.9861694854. The cubic root of 20421236 is about 273.3342210296.

Adding to 20421236 its reverse (63212402), we get a palindrome (83633638).

The spelling of 20421236 in words is "twenty million, four hundred twenty-one thousand, two hundred thirty-six".