77781897 has 8 divisors (see below), whose sum is σ = 115232480. Its totient is φ = 51854580.

The previous prime is 77781889. The next prime is 77781923. The reversal of 77781897 is 79818777.

It is not a de Polignac number, because 77781897 - 2³ = 77781889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77781997) 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 7 ways as a sum of consecutive naturals, for example, 1440379 + ... + 1440432.

It is an arithmetic number, because the mean of its divisors is an integer number (14404060).

Almost surely, 2^77781897 is an apocalyptic number.

It is an amenable number.

77781897 is a deficient number, since it is larger than the sum of its proper divisors (37450583).

77781897 is a wasteful number, since it uses less digits than its factorization.

77781897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2880820 (or 2880814 counting only the distinct ones).

The product of its digits is 1382976, while the sum is 54.

The square root of 77781897 is about 8819.4045717384. The cubic root of 77781897 is about 426.8672572297.

The spelling of 77781897 in words is "seventy-seven million, seven hundred eighty-one thousand, eight hundred ninety-seven".