28025628001681 has 4 divisors (see below), whose sum is σ = 28025701230772. Its totient is φ = 28025554772592.

The previous prime is 28025628001603. The next prime is 28025628001741. The reversal of 28025628001681 is 18610082652082.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26370700128081 + 1654927873600 = 5135241^2 + 1286440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28025628001681 is a prime.

It is a super-2 number, since 2×28025628001681² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28025628001981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36037446 + ... + 36806911.

It is an arithmetic number, because the mean of its divisors is an integer number (7006425307693).

Almost surely, 2^{28025628001681} is an apocalyptic number.

It is an amenable number.

28025628001681 is a deficient number, since it is larger than the sum of its proper divisors (73229091).

28025628001681 is an equidigital number, since it uses as much as digits as its factorization.

28025628001681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73229090.

The product of its (nonzero) digits is 737280, while the sum is 49.

The spelling of 28025628001681 in words is "twenty-eight trillion, twenty-five billion, six hundred twenty-eight million, one thousand, six hundred eighty-one".