78440437 has 2 divisors, whose sum is σ = 78440438. Its totient is φ = 78440436.

The previous prime is 78440393. The next prime is 78440459. The reversal of 78440437 is 73404487.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70408881 + 8031556 = 8391^2 + 2834^2 .

It is a cyclic number.

It is not a de Polignac number, because 78440437 - 2¹⁹ = 77916149 is a prime.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 78440396 and 78440405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78440237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39220218 + 39220219.

It is an arithmetic number, because the mean of its divisors is an integer number (39220219).

Almost surely, 2^78440437 is an apocalyptic number.

It is an amenable number.

78440437 is a deficient number, since it is larger than the sum of its proper divisors (1).

78440437 is an equidigital number, since it uses as much as digits as its factorization.

78440437 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 75264, while the sum is 37.

The square root of 78440437 is about 8856.6606009263. The cubic root of 78440437 is about 428.0685630545.

The spelling of 78440437 in words is "seventy-eight million, four hundred forty thousand, four hundred thirty-seven".