21781091522 has 8 divisors (see below), whose sum is σ = 34391197200. Its totient is φ = 10317359124.

The previous prime is 21781091491. The next prime is 21781091533. The reversal of 21781091522 is 22519018712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Harshad number since it is a multiple of its sum of digits (38), and also a Moran number because the ratio is a prime number: 573186619 = 21781091522 / (2 + 1 + 7 + 8 + 1 + 0 + 9 + 1 + 5 + 2 + 2).

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 286593272 + ... + 286593347.

It is an arithmetic number, because the mean of its divisors is an integer number (4298899650).

Almost surely, 2^21781091522 is an apocalyptic number.

21781091522 is a deficient number, since it is larger than the sum of its proper divisors (12610105678).

21781091522 is a wasteful number, since it uses less digits than its factorization.

21781091522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573186640.

The product of its (nonzero) digits is 20160, while the sum is 38.

The spelling of 21781091522 in words is "twenty-one billion, seven hundred eighty-one million, ninety-one thousand, five hundred twenty-two".