77944978 has 4 divisors (see below), whose sum is σ = 116917470. Its totient is φ = 38972488.

The previous prime is 77944969. The next prime is 77945081. The reversal of 77944978 is 87944977.

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

It can be written as a sum of positive squares in only one way, i.e., 45603009 + 32341969 = 6753^2 + 5687^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 19486243 + ... + 19486246.

Almost surely, 2^77944978 is an apocalyptic number.

77944978 is a deficient number, since it is larger than the sum of its proper divisors (38972492).

77944978 is a wasteful number, since it uses less digits than its factorization.

77944978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38972491.

The product of its digits is 3556224, while the sum is 55.

The square root of 77944978 is about 8828.6453094458. The cubic root of 77944978 is about 427.1653786288.

Subtracting 77944978 from its reverse (87944977), we obtain a palindrome (9999999).

The spelling of 77944978 in words is "seventy-seven million, nine hundred forty-four thousand, nine hundred seventy-eight".