20281636 has 12 divisors (see below), whose sum is σ = 35825328. Its totient is φ = 10045832.

The previous prime is 20281621. The next prime is 20281673. The reversal of 20281636 is 63618202.

It is a super-2 number, since 2×20281636² = 822689517672992, which contains 22 as substring.

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, 23266 + ... + 24121.

It is an arithmetic number, because the mean of its divisors is an integer number (2985444).

Almost surely, 2^20281636 is an apocalyptic number.

It is an amenable number.

20281636 is a deficient number, since it is larger than the sum of its proper divisors (15543692).

20281636 is a wasteful number, since it uses less digits than its factorization.

20281636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47498 (or 47496 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 20281636 is about 4503.5137392929. The cubic root of 20281636 is about 272.7099568669.

Adding to 20281636 its reverse (63618202), we get a palindrome (83899838).

The spelling of 20281636 in words is "twenty million, two hundred eighty-one thousand, six hundred thirty-six".