77822021878 has 4 divisors (see below), whose sum is σ = 116733032820. Its totient is φ = 38911010938.

The previous prime is 77822021861. The next prime is 77822021941. The reversal of 77822021878 is 87812022877.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19455505468 + ... + 19455505471.

It is an arithmetic number, because the mean of its divisors is an integer number (29183258205).

Almost surely, 2^77822021878 is an apocalyptic number.

77822021878 is a deficient number, since it is larger than the sum of its proper divisors (38911010942).

77822021878 is a wasteful number, since it uses less digits than its factorization.

77822021878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38911010941.

The product of its (nonzero) digits is 1404928, while the sum is 52.

Subtracting 77822021878 from its reverse (87812022877), we obtain a palindrome (9990000999).

The spelling of 77822021878 in words is "seventy-seven billion, eight hundred twenty-two million, twenty-one thousand, eight hundred seventy-eight".