78505257 has 8 divisors (see below), whose sum is σ = 104944320. Its totient is φ = 52201520.

The previous prime is 78505249. The next prime is 78505267. The reversal of 78505257 is 75250587.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78505257 - 2³ = 78505249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78505267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32469 + ... + 34802.

It is an arithmetic number, because the mean of its divisors is an integer number (13118040).

Almost surely, 2^78505257 is an apocalyptic number.

It is an amenable number.

78505257 is a deficient number, since it is larger than the sum of its proper divisors (26439063).

78505257 is a wasteful number, since it uses less digits than its factorization.

78505257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67663.

The product of its (nonzero) digits is 98000, while the sum is 39.

The square root of 78505257 is about 8860.3192380410. The cubic root of 78505257 is about 428.1864434306.

The spelling of 78505257 in words is "seventy-eight million, five hundred five thousand, two hundred fifty-seven".