21819826810 has 16 divisors (see below), whose sum is σ = 39277475496. Its totient is φ = 8727533568.

The previous prime is 21819826793. The next prime is 21819826877. The reversal of 21819826810 is 1862891812.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 15781138129 + 6038688681 = 125623^2 + 77709^2 .

It is a super-2 number, since 2×21819826810² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 295102 + ... + 361558.

Almost surely, 2^21819826810 is an apocalyptic number.

21819826810 is a deficient number, since it is larger than the sum of its proper divisors (17457648686).

21819826810 is a wasteful number, since it uses less digits than its factorization.

21819826810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99297.

The product of its (nonzero) digits is 110592, while the sum is 46.

The spelling of 21819826810 in words is "twenty-one billion, eight hundred nineteen million, eight hundred twenty-six thousand, eight hundred ten".