77820671 has 4 divisors (see below), whose sum is σ = 77861712. Its totient is φ = 77779632.

The previous prime is 77820667. The next prime is 77820683. The reversal of 77820671 is 17602877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17602877 = 1279 ⋅13763.

It is a cyclic number.

It is not a de Polignac number, because 77820671 - 2² = 77820667 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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17531 + ... + 21516.

It is an arithmetic number, because the mean of its divisors is an integer number (19465428).

Almost surely, 2^77820671 is an apocalyptic number.

77820671 is a deficient number, since it is larger than the sum of its proper divisors (41041).

77820671 is a wasteful number, since it uses less digits than its factorization.

77820671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41040.

The product of its (nonzero) digits is 32928, while the sum is 38.

The square root of 77820671 is about 8821.6025188171. The cubic root of 77820671 is about 426.9381760517.

The spelling of 77820671 in words is "seventy-seven million, eight hundred twenty thousand, six hundred seventy-one".