20421536 has 24 divisors (see below), whose sum is σ = 40966884. Its totient is φ = 10017280.

The previous prime is 20421503. The next prime is 20421553. The reversal of 20421536 is 63512402.

It can be written as a sum of positive squares in 2 ways, for example, as 19749136 + 672400 = 4444^2 + 820^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4325 + ... + 7716.

Almost surely, 2^20421536 is an apocalyptic number.

It is an amenable number.

20421536 is an abundant number, since it is smaller than the sum of its proper divisors (20545348).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20421536 is a wasteful number, since it uses less digits than its factorization.

20421536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12104 (or 12096 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 20421536 is about 4519.0193626494. The cubic root of 20421536 is about 273.3355595033.

Adding to 20421536 its reverse (63512402), we get a palindrome (83933938).

The spelling of 20421536 in words is "twenty million, four hundred twenty-one thousand, five hundred thirty-six".