28400590921 has 2 divisors, whose sum is σ = 28400590922. Its totient is φ = 28400590920.

The previous prime is 28400590913. The next prime is 28400590951. The reversal of 28400590921 is 12909500482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26370187321 + 2030403600 = 162389^2 + 45060^2 .

It is a cyclic number.

It is not a de Polignac number, because 28400590921 - 2³ = 28400590913 is a prime.

It is not a weakly prime, because it can be changed into another prime (28400590951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14200295460 + 14200295461.

It is an arithmetic number, because the mean of its divisors is an integer number (14200295461).

Almost surely, 2^28400590921 is an apocalyptic number.

It is an amenable number.

28400590921 is a deficient number, since it is larger than the sum of its proper divisors (1).

28400590921 is an equidigital number, since it uses as much as digits as its factorization.

28400590921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 40.

The spelling of 28400590921 in words is "twenty-eight billion, four hundred million, five hundred ninety thousand, nine hundred twenty-one".