77889421 has 2 divisors, whose sum is σ = 77889422. Its totient is φ = 77889420.

The previous prime is 77889407. The next prime is 77889437. The reversal of 77889421 is 12498877.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39312900 + 38576521 = 6270^2 + 6211^2 .

It is an emirp because it is prime and its reverse (12498877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77889421 - 2¹¹ = 77887373 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77889401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38944710 + 38944711.

It is an arithmetic number, because the mean of its divisors is an integer number (38944711).

Almost surely, 2^77889421 is an apocalyptic number.

It is an amenable number.

77889421 is a deficient number, since it is larger than the sum of its proper divisors (1).

77889421 is an equidigital number, since it uses as much as digits as its factorization.

77889421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 225792, while the sum is 46.

The square root of 77889421 is about 8825.4983428699. The cubic root of 77889421 is about 427.0638639950.

The spelling of 77889421 in words is "seventy-seven million, eight hundred eighty-nine thousand, four hundred twenty-one".