128027521 has 2 divisors, whose sum is σ = 128027522. Its totient is φ = 128027520.

The previous prime is 128027513. The next prime is 128027539. The reversal of 128027521 is 125720821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 124567921 + 3459600 = 11161^2 + 1860^2 .

It is an emirp because it is prime and its reverse (125720821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128027521 - 2³ = 128027513 is a prime.

It is a super-2 number, since 2×128027521² = 32782092266810882, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 128027521.

It is not a weakly prime, because it can be changed into another prime (128027021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64013760 + 64013761.

It is an arithmetic number, because the mean of its divisors is an integer number (64013761).

Almost surely, 2^128027521 is an apocalyptic number.

It is an amenable number.

128027521 is a deficient number, since it is larger than the sum of its proper divisors (1).

128027521 is an equidigital number, since it uses as much as digits as its factorization.

128027521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 128027521 is about 11314.9247014728. The cubic root of 128027521 is about 504.0045364188.

The spelling of 128027521 in words is "one hundred twenty-eight million, twenty-seven thousand, five hundred twenty-one".