77309861 has 4 divisors (see below), whose sum is σ = 77350572. Its totient is φ = 77269152.

The previous prime is 77309857. The next prime is 77309891. The reversal of 77309861 is 16890377.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27888961 + 49420900 = 5281^2 + 7030^2 .

It is a cyclic number.

It is not a de Polignac number, because 77309861 - 2² = 77309857 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 (77309801) 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, 17360 + ... + 21353.

It is an arithmetic number, because the mean of its divisors is an integer number (19337643).

Almost surely, 2^77309861 is an apocalyptic number.

It is an amenable number.

77309861 is a deficient number, since it is larger than the sum of its proper divisors (40711).

77309861 is a wasteful number, since it uses less digits than its factorization.

77309861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40710.

The product of its (nonzero) digits is 63504, while the sum is 41.

The square root of 77309861 is about 8792.6026294835. The cubic root of 77309861 is about 426.0019929080.

The spelling of 77309861 in words is "seventy-seven million, three hundred nine thousand, eight hundred sixty-one".