21761536 has 40 divisors (see below), whose sum is σ = 45789480. Its totient is φ = 10303488.

The previous prime is 21761527. The next prime is 21761539. The reversal of 21761536 is 63516712.

It is a junction number, because it is equal to n+sod(n) for n = 21761498 and 21761507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21761539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8610 + ... + 10846.

It is an arithmetic number, because the mean of its divisors is an integer number (1144737).

Almost surely, 2^21761536 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 21761536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22894740).

21761536 is an abundant number, since it is smaller than the sum of its proper divisors (24027944).

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

21761536 is an equidigital number, since it uses as much as digits as its factorization.

21761536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2274 (or 2258 counting only the distinct ones).

The product of its digits is 7560, while the sum is 31.

The square root of 21761536 is about 4664.9261516127. The cubic root of 21761536 is about 279.1878506931.

The spelling of 21761536 in words is "twenty-one million, seven hundred sixty-one thousand, five hundred thirty-six".