77422321021 has 4 divisors (see below), whose sum is σ = 77422965372. Its totient is φ = 77421676672.

The previous prime is 77422320973. The next prime is 77422321027. The reversal of 77422321021 is 12012322477.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12012322477 = 61843 ⋅194239.

It can be written as a sum of positive squares in 2 ways, for example, as 65812258521 + 11610062500 = 256539^2 + 107750^2 .

It is a cyclic number.

It is not a de Polignac number, because 77422321021 - 2³¹ = 75274837373 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 (77422321027) 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, 82516 + ... + 402061.

It is an arithmetic number, because the mean of its divisors is an integer number (19355741343).

Almost surely, 2^77422321021 is an apocalyptic number.

It is an amenable number.

77422321021 is a deficient number, since it is larger than the sum of its proper divisors (644351).

77422321021 is a wasteful number, since it uses less digits than its factorization.

77422321021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644350.

The product of its (nonzero) digits is 9408, while the sum is 31.

Adding to 77422321021 its reverse (12012322477), we get a palindrome (89434643498).

The spelling of 77422321021 in words is "seventy-seven billion, four hundred twenty-two million, three hundred twenty-one thousand, twenty-one".