77721983 has 2 divisors, whose sum is σ = 77721984. Its totient is φ = 77721982.

The previous prime is 77721971. The next prime is 77721997. The reversal of 77721983 is 38912777.

It is a weak prime.

It is an emirp because it is prime and its reverse (38912777) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77721983 - 2⁸ = 77721727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77721923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38860991 + 38860992.

It is an arithmetic number, because the mean of its divisors is an integer number (38860992).

Almost surely, 2^77721983 is an apocalyptic number.

77721983 is a deficient number, since it is larger than the sum of its proper divisors (1).

77721983 is an equidigital number, since it uses as much as digits as its factorization.

77721983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 148176, while the sum is 44.

The square root of 77721983 is about 8816.0072028101. The cubic root of 77721983 is about 426.7576263456.

The spelling of 77721983 in words is "seventy-seven million, seven hundred twenty-one thousand, nine hundred eighty-three".