20551236 has 48 divisors (see below), whose sum is σ = 52684800. Its totient is φ = 6206112.

The previous prime is 20551231. The next prime is 20551241. The reversal of 20551236 is 63215502.

It is an interprime number because it is at equal distance from previous prime (20551231) and next prime (20551241).

It is a super-2 number, since 2×20551236² = 844706602255392, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20551231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3285 + ... + 7203.

It is an arithmetic number, because the mean of its divisors is an integer number (1097600).

Almost surely, 2^20551236 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20551236, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26342400).

20551236 is an abundant number, since it is smaller than the sum of its proper divisors (32133564).

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

20551236 is a wasteful number, since it uses less digits than its factorization.

20551236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3968 (or 3966 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 20551236 is about 4533.3471078222. The cubic root of 20551236 is about 273.9130027320.

Adding to 20551236 its reverse (63215502), we get a palindrome (83766738).

The spelling of 20551236 in words is "twenty million, five hundred fifty-one thousand, two hundred thirty-six".