78306644 has 24 divisors (see below), whose sum is σ = 147926688. Its totient is φ = 36056160.

The previous prime is 78306587. The next prime is 78306649. The reversal of 78306644 is 44660387.

It is a happy number.

It is a super-2 number, since 2×78306644² = 12263860989085472, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 78306598 and 78306607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78306649) 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, 23999 + ... + 27065.

It is an arithmetic number, because the mean of its divisors is an integer number (6163612).

Almost surely, 2^78306644 is an apocalyptic number.

It is an amenable number.

78306644 is a deficient number, since it is larger than the sum of its proper divisors (69620044).

78306644 is a wasteful number, since it uses less digits than its factorization.

78306644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3575 (or 3573 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 38.

The square root of 78306644 is about 8849.1041354478. The cubic root of 78306644 is about 427.8250442228.

The spelling of 78306644 in words is "seventy-eight million, three hundred six thousand, six hundred forty-four".