28135575821 has 2 divisors, whose sum is σ = 28135575822. Its totient is φ = 28135575820.

The previous prime is 28135575817. The next prime is 28135575847. The reversal of 28135575821 is 12857553182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28127985796 + 7590025 = 167714^2 + 2755^2 .

It is a cyclic number.

It is not a de Polignac number, because 28135575821 - 2² = 28135575817 is a prime.

It is a super-2 number, since 2×28135575821² (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 (28135505821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14067787910 + 14067787911.

It is an arithmetic number, because the mean of its divisors is an integer number (14067787911).

Almost surely, 2^28135575821 is an apocalyptic number.

It is an amenable number.

28135575821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28135575821 is an equidigital number, since it uses as much as digits as its factorization.

28135575821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672000, while the sum is 47.

The spelling of 28135575821 in words is "twenty-eight billion, one hundred thirty-five million, five hundred seventy-five thousand, eight hundred twenty-one".