21820686548 has 6 divisors (see below), whose sum is σ = 38186201466. Its totient is φ = 10910343272.

The previous prime is 21820686497. The next prime is 21820686557. The reversal of 21820686548 is 84568602812.

It can be written as a sum of positive squares in only one way, i.e., 11694692164 + 10125994384 = 108142^2 + 100628^2 .

It is a super-2 number, since 2×21820686548² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21820686496 and 21820686505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2727585815 + ... + 2727585822.

It is an arithmetic number, because the mean of its divisors is an integer number (6364366911).

Almost surely, 2^21820686548 is an apocalyptic number.

It is an amenable number.

21820686548 is a deficient number, since it is larger than the sum of its proper divisors (16365514918).

21820686548 is a wasteful number, since it uses less digits than its factorization.

21820686548 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5455171641 (or 5455171639 counting only the distinct ones).

The product of its (nonzero) digits is 1474560, while the sum is 50.

The spelling of 21820686548 in words is "twenty-one billion, eight hundred twenty million, six hundred eighty-six thousand, five hundred forty-eight".