78967781 has 4 divisors (see below), whose sum is σ = 83124000. Its totient is φ = 74811564.

The previous prime is 78967769. The next prime is 78967789. The reversal of 78967781 is 18776987.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18776987 = 73 ⋅257219.

It is a cyclic number.

It is not a de Polignac number, because 78967781 - 2²² = 74773477 is a prime.

It is a super-2 number, since 2×78967781² = 12471820872127922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78967789) 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, 2078081 + ... + 2078118.

It is an arithmetic number, because the mean of its divisors is an integer number (20781000).

Almost surely, 2^78967781 is an apocalyptic number.

It is an amenable number.

78967781 is a deficient number, since it is larger than the sum of its proper divisors (4156219).

78967781 is a wasteful number, since it uses less digits than its factorization.

78967781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4156218.

The product of its digits is 1185408, while the sum is 53.

The square root of 78967781 is about 8886.3817721275. The cubic root of 78967781 is about 429.0257028773.

The spelling of 78967781 in words is "seventy-eight million, nine hundred sixty-seven thousand, seven hundred eighty-one".