21707136 has 128 divisors (see below), whose sum is σ = 70012800. Its totient is φ = 6566400.

The previous prime is 21707117. The next prime is 21707137. The reversal of 21707136 is 63170712.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21707137) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37731 + ... + 38301.

It is an arithmetic number, because the mean of its divisors is an integer number (546975).

Almost surely, 2^21707136 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 21707136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35006400).

21707136 is an abundant number, since it is smaller than the sum of its proper divisors (48305664).

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

21707136 is a wasteful number, since it uses less digits than its factorization.

21707136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 605 (or 587 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 21707136 is about 4659.0917569844. The cubic root of 21707136 is about 278.9550164498.

Adding to 21707136 its reverse (63170712), we get a palindrome (84877848).

The spelling of 21707136 in words is "twenty-one million, seven hundred seven thousand, one hundred thirty-six".