78400785 has 16 divisors (see below), whose sum is σ = 127031040. Its totient is φ = 41283840.

The previous prime is 78400781. The next prime is 78400789. The reversal of 78400785 is 58700487.

It is an interprime number because it is at equal distance from previous prime (78400781) and next prime (78400789).

It is not a de Polignac number, because 78400785 - 2² = 78400781 is a prime.

It is a super-2 number, since 2×78400785² = 12293366177232450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78400781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31896 + ... + 34265.

It is an arithmetic number, because the mean of its divisors is an integer number (7939440).

Almost surely, 2^78400785 is an apocalyptic number.

It is an amenable number.

78400785 is a deficient number, since it is larger than the sum of its proper divisors (48630255).

78400785 is a wasteful number, since it uses less digits than its factorization.

78400785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66248.

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 78400785 is about 8854.4217767170. The cubic root of 78400785 is about 427.9964206909.

The spelling of 78400785 in words is "seventy-eight million, four hundred thousand, seven hundred eighty-five".