771861 has 4 divisors (see below), whose sum is σ = 1029152. Its totient is φ = 514572.

The previous prime is 771853. The next prime is 771863. The reversal of 771861 is 168177.

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 not a de Polignac number, because 771861 - 2³ = 771853 is a prime.

It is a D-number.

It is a Duffinian number.

771861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (771863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128641 + ... + 128646.

It is an arithmetic number, because the mean of its divisors is an integer number (257288).

2⁷⁷¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

771861 is a deficient number, since it is larger than the sum of its proper divisors (257291).

771861 is a wasteful number, since it uses less digits than its factorization.

771861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257290.

The product of its digits is 2352, while the sum is 30.

The square root of 771861 is about 878.5562019586. The cubic root of 771861 is about 91.7303462024.

The spelling of 771861 in words is "seven hundred seventy-one thousand, eight hundred sixty-one".