78125491 has 2 divisors, whose sum is σ = 78125492. Its totient is φ = 78125490.

The previous prime is 78125479. The next prime is 78125497. The reversal of 78125491 is 19452187.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78125491 - 2¹¹ = 78123443 is a prime.

It is a super-2 number, since 2×78125491² = 12207184687982162, which contains 22 as substring.

It is equal to p_4566484 and since 78125491 and 4566484 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78125491.

It is not a weakly prime, because it can be changed into another prime (78125497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39062745 + 39062746.

It is an arithmetic number, because the mean of its divisors is an integer number (39062746).

Almost surely, 2^78125491 is an apocalyptic number.

78125491 is a deficient number, since it is larger than the sum of its proper divisors (1).

78125491 is an equidigital number, since it uses as much as digits as its factorization.

78125491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 37.

The square root of 78125491 is about 8838.8625399426. The cubic root of 78125491 is about 427.4948822387.

The spelling of 78125491 in words is "seventy-eight million, one hundred twenty-five thousand, four hundred ninety-one".