78391267 has 4 divisors (see below), whose sum is σ = 83002536. Its totient is φ = 73780000.

The previous prime is 78391249. The next prime is 78391297. The reversal of 78391267 is 76219387.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76219387 = 641 ⋅118907.

It is not a de Polignac number, because 78391267 - 2¹⁹ = 77866979 is a prime.

It is a super-2 number, since 2×78391267² = 12290381483730578, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78391217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2305609 + ... + 2305642.

It is an arithmetic number, because the mean of its divisors is an integer number (20750634).

Almost surely, 2^78391267 is an apocalyptic number.

78391267 is a deficient number, since it is larger than the sum of its proper divisors (4611269).

78391267 is a wasteful number, since it uses less digits than its factorization.

78391267 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4611268.

The product of its digits is 127008, while the sum is 43.

The square root of 78391267 is about 8853.8842888305. The cubic root of 78391267 is about 427.9791001382.

The spelling of 78391267 in words is "seventy-eight million, three hundred ninety-one thousand, two hundred sixty-seven".