77781966 has 16 divisors (see below), whose sum is σ = 155705088. Its totient is φ = 25903800.

The previous prime is 77781937. The next prime is 77781971. The reversal of 77781966 is 66918777.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2121 + ... + 12651.

It is an arithmetic number, because the mean of its divisors is an integer number (9731568).

Almost surely, 2^77781966 is an apocalyptic number.

77781966 is an abundant number, since it is smaller than the sum of its proper divisors (77923122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77781966 is a wasteful number, since it uses less digits than its factorization.

77781966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11767.

The product of its digits is 889056, while the sum is 51.

The square root of 77781966 is about 8819.4084835662. The cubic root of 77781966 is about 426.8673834537.

The spelling of 77781966 in words is "seventy-seven million, seven hundred eighty-one thousand, nine hundred sixty-six".