78512101 has 2 divisors, whose sum is σ = 78512102. Its totient is φ = 78512100.

The previous prime is 78512081. The next prime is 78512129. The reversal of 78512101 is 10121587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76580001 + 1932100 = 8751^2 + 1390^2 .

It is a cyclic number.

It is not a de Polignac number, because 78512101 - 2¹⁵ = 78479333 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78512131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39256050 + 39256051.

It is an arithmetic number, because the mean of its divisors is an integer number (39256051).

Almost surely, 2^78512101 is an apocalyptic number.

It is an amenable number.

78512101 is a deficient number, since it is larger than the sum of its proper divisors (1).

78512101 is an equidigital number, since it uses as much as digits as its factorization.

78512101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 78512101 is about 8860.7054459563. The cubic root of 78512101 is about 428.1988860066.

Adding to 78512101 its reverse (10121587), we get a palindrome (88633688).

The spelling of 78512101 in words is "seventy-eight million, five hundred twelve thousand, one hundred one".