21056621882 has 8 divisors (see below), whose sum is σ = 31593141876. Its totient is φ = 10525574592.

The previous prime is 21056621867. The next prime is 21056621891. The reversal of 21056621882 is 28812665012.

It is a happy number.

It is a Cunningham number, because it is equal to 145109²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 21056621881 + 1 = 145109^2 + 1^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1358543 + ... + 1373954.

Almost surely, 2^21056621882 is an apocalyptic number.

21056621882 is a deficient number, since it is larger than the sum of its proper divisors (10536519994).

21056621882 is a wasteful number, since it uses less digits than its factorization.

21056621882 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2736352.

The product of its (nonzero) digits is 92160, while the sum is 41.

The spelling of 21056621882 in words is "twenty-one billion, fifty-six million, six hundred twenty-one thousand, eight hundred eighty-two".