78278457 has 8 divisors (see below), whose sum is σ = 104426784. Its totient is φ = 52157888.

The previous prime is 78278443. The next prime is 78278477. The reversal of 78278457 is 75487287.

It is a happy number.

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 78278457 - 2⁶ = 78278393 is a prime.

It is a super-2 number, since 2×78278457² = 12255033660601698, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78278477) 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, 913 + ... + 12545.

It is an arithmetic number, because the mean of its divisors is an integer number (13053348).

Almost surely, 2^78278457 is an apocalyptic number.

It is an amenable number.

78278457 is a deficient number, since it is larger than the sum of its proper divisors (26148327).

78278457 is a wasteful number, since it uses less digits than its factorization.

78278457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13879.

The product of its digits is 878080, while the sum is 48.

The square root of 78278457 is about 8847.5113450054. The cubic root of 78278457 is about 427.7737052341.

The spelling of 78278457 in words is "seventy-eight million, two hundred seventy-eight thousand, four hundred fifty-seven".