21782436 has 48 divisors (see below), whose sum is σ = 57624000. Its totient is φ = 6348672.

The previous prime is 21782419. The next prime is 21782447. The reversal of 21782436 is 63428712.

It is a junction number, because it is equal to n+sod(n) for n = 21782397 and 21782406.

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 15 ways as a sum of consecutive naturals, for example, 711 + ... + 6638.

It is an arithmetic number, because the mean of its divisors is an integer number (1200500).

Almost surely, 2^21782436 is an apocalyptic number.

21782436 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 21782436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28812000).

21782436 is an abundant number, since it is smaller than the sum of its proper divisors (35841564).

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

21782436 is a wasteful number, since it uses less digits than its factorization.

21782436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7388 (or 7386 counting only the distinct ones).

The product of its digits is 16128, while the sum is 33.

The square root of 21782436 is about 4667.1657352188. The cubic root of 21782436 is about 279.2772003767.

The spelling of 21782436 in words is "twenty-one million, seven hundred eighty-two thousand, four hundred thirty-six".