78649451 has 4 divisors (see below), whose sum is σ = 80478552. Its totient is φ = 76820352.

The previous prime is 78649427. The next prime is 78649481. The reversal of 78649451 is 15494687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15494687 = 13 ⋅1191899.

It is a cyclic number.

It is not a de Polignac number, because 78649451 - 2¹⁸ = 78387307 is a prime.

It is a super-2 number, since 2×78649451² = 12371472285202802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78649481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 914486 + ... + 914571.

It is an arithmetic number, because the mean of its divisors is an integer number (20119638).

Almost surely, 2^78649451 is an apocalyptic number.

78649451 is a deficient number, since it is larger than the sum of its proper divisors (1829101).

78649451 is a wasteful number, since it uses less digits than its factorization.

78649451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829100.

The product of its digits is 241920, while the sum is 44.

The square root of 78649451 is about 8868.4525707702. The cubic root of 78649451 is about 428.4484392747.

The spelling of 78649451 in words is "seventy-eight million, six hundred forty-nine thousand, four hundred fifty-one".