20897536 has 72 divisors (see below), whose sum is σ = 46873008. Its totient is φ = 9216000.

The previous prime is 20897533. The next prime is 20897543. The reversal of 20897536 is 63579802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20897533) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 115366 + ... + 115546.

It is an arithmetic number, because the mean of its divisors is an integer number (651014).

It is a vampire number, since it can be written as 3608 ⋅ 5792 (with its own digits).

Almost surely, 2^20897536 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 20897536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23436504).

20897536 is an abundant number, since it is smaller than the sum of its proper divisors (25975472).

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

20897536 is a wasteful number, since it uses less digits than its factorization.

20897536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249 (or 235 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 20897536 is about 4571.3822854800. The cubic root of 20897536 is about 275.4429709263.

The spelling of 20897536 in words is "twenty million, eight hundred ninety-seven thousand, five hundred thirty-six".