21527576138 has 4 divisors (see below), whose sum is σ = 32291364210. Its totient is φ = 10763788068.

The previous prime is 21527576129. The next prime is 21527576141. The reversal of 21527576138 is 83167572512.

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., 16619592889 + 4907983249 = 128917^2 + 70057^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21527576092 and 21527576101.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5381894033 + ... + 5381894036.

Almost surely, 2^21527576138 is an apocalyptic number.

21527576138 is a deficient number, since it is larger than the sum of its proper divisors (10763788072).

21527576138 is a wasteful number, since it uses less digits than its factorization.

21527576138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10763788071.

The product of its digits is 705600, while the sum is 47.

The spelling of 21527576138 in words is "twenty-one billion, five hundred twenty-seven million, five hundred seventy-six thousand, one hundred thirty-eight".