20021236 has 6 divisors (see below), whose sum is σ = 35037170. Its totient is φ = 10010616.

The previous prime is 20021233. The next prime is 20021251. The reversal of 20021236 is 63212002.

It can be written as a sum of positive squares in only one way, i.e., 19412836 + 608400 = 4406^2 + 780^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2502651 + ... + 2502658.

Almost surely, 2^20021236 is an apocalyptic number.

It is an amenable number.

20021236 is a deficient number, since it is larger than the sum of its proper divisors (15015934).

20021236 is a wasteful number, since it uses less digits than its factorization.

20021236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5005313 (or 5005311 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 20021236 is about 4474.5095820659. The cubic root of 20021236 is about 271.5377999639.

Adding to 20021236 its reverse (63212002), we get a palindrome (83233238).

The spelling of 20021236 in words is "twenty million, twenty-one thousand, two hundred thirty-six".