78539401 has 2 divisors, whose sum is σ = 78539402. Its totient is φ = 78539400.

The previous prime is 78539393. The next prime is 78539413. The reversal of 78539401 is 10493587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73359225 + 5180176 = 8565^2 + 2276^2 .

It is a cyclic number.

It is not a de Polignac number, because 78539401 - 2³ = 78539393 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78539441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39269700 + 39269701.

It is an arithmetic number, because the mean of its divisors is an integer number (39269701).

Almost surely, 2^78539401 is an apocalyptic number.

It is an amenable number.

78539401 is a deficient number, since it is larger than the sum of its proper divisors (1).

78539401 is an equidigital number, since it uses as much as digits as its factorization.

78539401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 78539401 is about 8862.2458214608. The cubic root of 78539401 is about 428.2485109467.

It can be divided in two parts, 785 and 39401, that added together give a triangular number (40186 = T₂₈₃).

The spelling of 78539401 in words is "seventy-eight million, five hundred thirty-nine thousand, four hundred one".