21582666738 has 12 divisors (see below), whose sum is σ = 46762444638. Its totient is φ = 7194222240.

The previous prime is 21582666733. The next prime is 21582666773. The reversal of 21582666738 is 83766628512.

It can be written as a sum of positive squares in only one way, i.e., 11579266449 + 10003400289 = 107607^2 + 100017^2 .

It is not an unprimeable number, because it can be changed into a prime (21582666733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 599518503 + ... + 599518538.

Almost surely, 2^21582666738 is an apocalyptic number.

21582666738 is an abundant number, since it is smaller than the sum of its proper divisors (25179777900).

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

21582666738 is a wasteful number, since it uses less digits than its factorization.

21582666738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1199037049 (or 1199037046 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 54.

The spelling of 21582666738 in words is "twenty-one billion, five hundred eighty-two million, six hundred sixty-six thousand, seven hundred thirty-eight".