20897136 has 120 divisors (see below), whose sum is σ = 65672880. Its totient is φ = 6324480.

The previous prime is 20897117. The next prime is 20897143. The reversal of 20897136 is 63179802.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 20897136.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 342546 + ... + 342606.

It is an arithmetic number, because the mean of its divisors is an integer number (547274).

Almost surely, 2^20897136 is an apocalyptic number.

20897136 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20897136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32836440).

20897136 is an abundant number, since it is smaller than the sum of its proper divisors (44775744).

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

20897136 is a wasteful number, since it uses less digits than its factorization.

20897136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 79 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 20897136 is about 4571.3385348276. The cubic root of 20897136 is about 275.4412134960.

It can be divided in two parts, 208 and 97136, that added together give a square (97344 = 312²).

The spelling of 20897136 in words is "twenty million, eight hundred ninety-seven thousand, one hundred thirty-six".