21782578242 has 16 divisors (see below), whose sum is σ = 43568158752. Its totient is φ = 7260359040.

The previous prime is 21782578231. The next prime is 21782578243. The reversal of 21782578242 is 24287528712.

It is a junction number, because it is equal to n+sod(n) for n = 21782578191 and 21782578200.

It is not an unprimeable number, because it can be changed into a prime (21782578243) 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, 24559 + ... + 210162.

It is an arithmetic number, because the mean of its divisors is an integer number (2723009922).

Almost surely, 2^21782578242 is an apocalyptic number.

21782578242 is an abundant number, since it is smaller than the sum of its proper divisors (21785580510).

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

21782578242 is a wasteful number, since it uses less digits than its factorization.

21782578242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250193.

The product of its digits is 1003520, while the sum is 48.

The spelling of 21782578242 in words is "twenty-one billion, seven hundred eighty-two million, five hundred seventy-eight thousand, two hundred forty-two".