77861807 has 4 divisors (see below), whose sum is σ = 77881920. Its totient is φ = 77841696.

The previous prime is 77861783. The next prime is 77861837. The reversal of 77861807 is 70816877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70816877 = 311 ⋅227707.

It is a cyclic number.

It is not a de Polignac number, because 77861807 - 2²⁴ = 61084591 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 (77861837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2207 + ... + 12672.

It is an arithmetic number, because the mean of its divisors is an integer number (19470480).

Almost surely, 2^77861807 is an apocalyptic number.

77861807 is a deficient number, since it is larger than the sum of its proper divisors (20113).

77861807 is a wasteful number, since it uses less digits than its factorization.

77861807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20112.

The product of its (nonzero) digits is 131712, while the sum is 44.

The square root of 77861807 is about 8823.9337599508. The cubic root of 77861807 is about 427.0133892951.

The spelling of 77861807 in words is "seventy-seven million, eight hundred sixty-one thousand, eight hundred seven".