78278249 has 16 divisors (see below), whose sum is σ = 91054080. Its totient is φ = 65912400.

The previous prime is 78278237. The next prime is 78278287. The reversal of 78278249 is 94287287.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 78278249 - 2²⁰ = 77229673 is a prime.

It is a super-2 number, since 2×78278249² = 12254968533012002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78278209) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108512 + ... + 109230.

It is an arithmetic number, because the mean of its divisors is an integer number (5690880).

Almost surely, 2^78278249 is an apocalyptic number.

It is an amenable number.

78278249 is a deficient number, since it is larger than the sum of its proper divisors (12775831).

78278249 is a wasteful number, since it uses less digits than its factorization.

78278249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 980.

The product of its digits is 451584, while the sum is 47.

The square root of 78278249 is about 8847.4995902797. The cubic root of 78278249 is about 427.7733263431.

The spelling of 78278249 in words is "seventy-eight million, two hundred seventy-eight thousand, two hundred forty-nine".