78405947 has 2 divisors, whose sum is σ = 78405948. Its totient is φ = 78405946.

The previous prime is 78405911. The next prime is 78405949. The reversal of 78405947 is 74950487.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78405947 - 2¹⁶ = 78340411 is a prime.

It is a super-2 number, since 2×78405947² = 12294985049933618, which contains 22 as substring.

Together with 78405949, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 78405898 and 78405907.

It is not a weakly prime, because it can be changed into another prime (78405949) 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, 39202973 + 39202974.

It is an arithmetic number, because the mean of its divisors is an integer number (39202974).

Almost surely, 2^78405947 is an apocalyptic number.

78405947 is a deficient number, since it is larger than the sum of its proper divisors (1).

78405947 is an equidigital number, since it uses as much as digits as its factorization.

78405947 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 282240, while the sum is 44.

The square root of 78405947 is about 8854.7132646969. The cubic root of 78405947 is about 428.0058137476.

The spelling of 78405947 in words is "seventy-eight million, four hundred five thousand, nine hundred forty-seven".