28078735621 has 2 divisors, whose sum is σ = 28078735622. Its totient is φ = 28078735620.

The previous prime is 28078735571. The next prime is 28078735631. The reversal of 28078735621 is 12653787082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27951158596 + 127577025 = 167186^2 + 11295^2 .

It is a cyclic number.

It is not a de Polignac number, because 28078735621 - 2¹³ = 28078727429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28078735631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14039367810 + 14039367811.

It is an arithmetic number, because the mean of its divisors is an integer number (14039367811).

Almost surely, 2^28078735621 is an apocalyptic number.

It is an amenable number.

28078735621 is a deficient number, since it is larger than the sum of its proper divisors (1).

28078735621 is an equidigital number, since it uses as much as digits as its factorization.

28078735621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1128960, while the sum is 49.

The spelling of 28078735621 in words is "twenty-eight billion, seventy-eight million, seven hundred thirty-five thousand, six hundred twenty-one".