28905742421 has 2 divisors, whose sum is σ = 28905742422. Its totient is φ = 28905742420.

The previous prime is 28905742403. The next prime is 28905742433. The reversal of 28905742421 is 12424750982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27282780625 + 1622961796 = 165175^2 + 40286^2 .

It is a cyclic number.

It is not a de Polignac number, because 28905742421 - 2⁶ = 28905742357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28905741421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14452871210 + 14452871211.

It is an arithmetic number, because the mean of its divisors is an integer number (14452871211).

Almost surely, 2^28905742421 is an apocalyptic number.

It is an amenable number.

28905742421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28905742421 is an equidigital number, since it uses as much as digits as its factorization.

28905742421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 322560, while the sum is 44.

The spelling of 28905742421 in words is "twenty-eight billion, nine hundred five million, seven hundred forty-two thousand, four hundred twenty-one".