21155944826 has 4 divisors (see below), whose sum is σ = 31733917242. Its totient is φ = 10577972412.

The previous prime is 21155944793. The next prime is 21155944829. The reversal of 21155944826 is 62844955112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17441164225 + 3714780601 = 132065^2 + 60949^2 .

It is not an unprimeable number, because it can be changed into a prime (21155944829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5288986205 + ... + 5288986208.

Almost surely, 2^21155944826 is an apocalyptic number.

21155944826 is a deficient number, since it is larger than the sum of its proper divisors (10577972416).

21155944826 is a wasteful number, since it uses less digits than its factorization.

21155944826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10577972415.

The product of its digits is 691200, while the sum is 47.

The spelling of 21155944826 in words is "twenty-one billion, one hundred fifty-five million, nine hundred forty-four thousand, eight hundred twenty-six".