77820647 has 8 divisors (see below), whose sum is σ = 78721536. Its totient is φ = 76924512.

The previous prime is 77820643. The next prime is 77820653. The reversal of 77820647 is 74602877.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77820647 - 2² = 77820643 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77820641) 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, 39293 + ... + 41225.

It is an arithmetic number, because the mean of its divisors is an integer number (9840192).

Almost surely, 2^77820647 is an apocalyptic number.

77820647 is a deficient number, since it is larger than the sum of its proper divisors (900889).

77820647 is a wasteful number, since it uses less digits than its factorization.

77820647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2377.

The product of its (nonzero) digits is 131712, while the sum is 41.

The square root of 77820647 is about 8821.6011585199. The cubic root of 77820647 is about 426.9381321623.

The spelling of 77820647 in words is "seventy-seven million, eight hundred twenty thousand, six hundred forty-seven".