20691536 has 40 divisors (see below), whose sum is σ = 42586560. Its totient is φ = 9718016.

The previous prime is 20691509. The next prime is 20691569. The reversal of 20691536 is 63519602.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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, 21236 + ... + 22188.

It is an arithmetic number, because the mean of its divisors is an integer number (1064664).

Almost surely, 2^20691536 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 20691536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21293280).

20691536 is an abundant number, since it is smaller than the sum of its proper divisors (21895024).

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

20691536 is a wasteful number, since it uses less digits than its factorization.

20691536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1043 (or 1037 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 20691536 is about 4548.7950052734. The cubic root of 20691536 is about 274.5349097332.

The spelling of 20691536 in words is "twenty million, six hundred ninety-one thousand, five hundred thirty-six".