77857861 has 4 divisors (see below), whose sum is σ = 78013152. Its totient is φ = 77702572.

The previous prime is 77857859. The next prime is 77857867. The reversal of 77857861 is 16875877.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77857861 - 2¹ = 77857859 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 (77857867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76891 + ... + 77896.

It is an arithmetic number, because the mean of its divisors is an integer number (19503288).

Almost surely, 2^77857861 is an apocalyptic number.

It is an amenable number.

77857861 is a deficient number, since it is larger than the sum of its proper divisors (155291).

77857861 is a wasteful number, since it uses less digits than its factorization.

77857861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155290.

The product of its digits is 658560, while the sum is 49.

The square root of 77857861 is about 8823.7101606977. The cubic root of 77857861 is about 427.0061755602.

The spelling of 77857861 in words is "seventy-seven million, eight hundred fifty-seven thousand, eight hundred sixty-one".