28307555981 has 2 divisors, whose sum is σ = 28307555982. Its totient is φ = 28307555980.

The previous prime is 28307555929. The next prime is 28307555987. The reversal of 28307555981 is 18955570382.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26333175625 + 1974380356 = 162275^2 + 44434^2 .

It is a cyclic number.

It is not a de Polignac number, because 28307555981 - 2²⁶ = 28240447117 is a prime.

It is a super-2 number, since 2×28307555981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28307555987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14153777990 + 14153777991.

It is an arithmetic number, because the mean of its divisors is an integer number (14153777991).

Almost surely, 2^28307555981 is an apocalyptic number.

It is an amenable number.

28307555981 is a deficient number, since it is larger than the sum of its proper divisors (1).

28307555981 is an equidigital number, since it uses as much as digits as its factorization.

28307555981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024000, while the sum is 53.

The spelling of 28307555981 in words is "twenty-eight billion, three hundred seven million, five hundred fifty-five thousand, nine hundred eighty-one".