21782844138 has 16 divisors (see below), whose sum is σ = 47526205536. Its totient is φ = 6600861840.

The previous prime is 21782844137. The next prime is 21782844169. The reversal of 21782844138 is 83144828712.

It is not an unprimeable number, because it can be changed into a prime (21782844131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165021481 + ... + 165021612.

It is an arithmetic number, because the mean of its divisors is an integer number (2970387846).

Almost surely, 2^21782844138 is an apocalyptic number.

21782844138 is an abundant number, since it is smaller than the sum of its proper divisors (25743361398).

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

21782844138 is a wasteful number, since it uses less digits than its factorization.

21782844138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330043109.

The product of its digits is 688128, while the sum is 48.

The spelling of 21782844138 in words is "twenty-one billion, seven hundred eighty-two million, eight hundred forty-four thousand, one hundred thirty-eight".