21413639556 has 63 divisors (see below), whose sum is σ = 56062098001. Its totient is φ = 6891746064.

The previous prime is 21413639503. The next prime is 21413639557. The reversal of 21413639556 is 65593631412.

The square root of 21413639556 is 146334.

It is a perfect power (a square), and thus also a powerful number.

21413639556 is a `hidden beast` number, since 2 + 1 + 4 + 1 + 3 + 639 + 5 + 5 + 6 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 9145861956 + 12267777600 = 95634^2 + 110760^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21413639557) by changing a digit.

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 20 ways as a sum of consecutive naturals, for example, 738401350 + ... + 738401378.

Almost surely, 2^21413639556 is an apocalyptic number.

21413639556 is the 146334-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21413639556

21413639556 is an abundant number, since it is smaller than the sum of its proper divisors (34648458445).

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

21413639556 is an frugal number, since it uses more digits than its factorization.

21413639556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184 (or 34 counting only the distinct ones).

The product of its digits is 583200, while the sum is 45.

It can be divided in two parts, 21413 and 639556, that added together give a square (660969 = 813²).

The spelling of 21413639556 in words is "twenty-one billion, four hundred thirteen million, six hundred thirty-nine thousand, five hundred fifty-six".