28720475477 has 2 divisors, whose sum is σ = 28720475478. Its totient is φ = 28720475476.

The previous prime is 28720475453. The next prime is 28720475489. The reversal of 28720475477 is 77457402782.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28031465476 + 689010001 = 167426^2 + 26249^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28720475477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28720405477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14360237738 + 14360237739.

It is an arithmetic number, because the mean of its divisors is an integer number (14360237739).

Almost surely, 2^28720475477 is an apocalyptic number.

It is an amenable number.

28720475477 is a deficient number, since it is larger than the sum of its proper divisors (1).

28720475477 is an equidigital number, since it uses as much as digits as its factorization.

28720475477 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6146560, while the sum is 53.

The spelling of 28720475477 in words is "twenty-eight billion, seven hundred twenty million, four hundred seventy-five thousand, four hundred seventy-seven".