21782891520 has 1408 divisors, whose sum is σ = 95080366080. Its totient is φ = 4671406080.

The previous prime is 21782891483. The next prime is 21782891521. The reversal of 21782891520 is 2519828712.

21782891520 is a `hidden beast` number, since 2 + 17 + 8 + 28 + 91 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21782891521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 702673905 + ... + 702673935.

Almost surely, 2^21782891520 is an apocalyptic number.

21782891520 is a gapful number since it is divisible by the number (20) 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 21782891520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47540183040).

21782891520 is an abundant number, since it is smaller than the sum of its proper divisors (73297474560).

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

21782891520 is a wasteful number, since it uses less digits than its factorization.

21782891520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 21782891520 in words is "twenty-one billion, seven hundred eighty-two million, eight hundred ninety-one thousand, five hundred twenty".