21520048868 has 6 divisors (see below), whose sum is σ = 37660085526. Its totient is φ = 10760024432.

The previous prime is 21520048843. The next prime is 21520048871. The reversal of 21520048868 is 86884002512.

It can be written as a sum of positive squares in only one way, i.e., 21205766884 + 314281984 = 145622^2 + 17728^2 .

It is a super-2 number, since 2×21520048868² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690006105 + ... + 2690006112.

It is an arithmetic number, because the mean of its divisors is an integer number (6276680921).

Almost surely, 2^21520048868 is an apocalyptic number.

It is an amenable number.

21520048868 is a deficient number, since it is larger than the sum of its proper divisors (16140036658).

21520048868 is a wasteful number, since it uses less digits than its factorization.

21520048868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5380012221 (or 5380012219 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 44.

The spelling of 21520048868 in words is "twenty-one billion, five hundred twenty million, forty-eight thousand, eight hundred sixty-eight".