28018082690521 has 27 divisors (see below), whose sum is σ = 35825295119733. Its totient is φ = 21831954633720.

The previous prime is 28018082690513. The next prime is 28018082690527. The reversal of 28018082690521 is 12509628081082.

The square root of 28018082690521 is 5293211.

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

It is not a de Polignac number, because 28018082690521 - 2³ = 28018082690513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28018082690527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 407542876 + ... + 407611618.

Almost surely, 2^{28018082690521} is an apocalyptic number.

28018082690521 is the 5293211-st square number.

28018082690521 is the 2646606-th centered octagonal number.

It is an amenable number.

28018082690521 is a deficient number, since it is larger than the sum of its proper divisors (7807212429212).

28018082690521 is an frugal number, since it uses more digits than its factorization.

28018082690521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137522 (or 68761 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 52.

The spelling of 28018082690521 in words is "twenty-eight trillion, eighteen billion, eighty-two million, six hundred ninety thousand, five hundred twenty-one".