77972000221 has 2 divisors, whose sum is σ = 77972000222. Its totient is φ = 77972000220.

The previous prime is 77972000219. The next prime is 77972000231. The reversal of 77972000221 is 12200027977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77946497721 + 25502500 = 279189^2 + 5050^2 .

It is a cyclic number.

It is not a de Polignac number, because 77972000221 - 2¹ = 77972000219 is a prime.

Together with 77972000219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77972000231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38986000110 + 38986000111.

It is an arithmetic number, because the mean of its divisors is an integer number (38986000111).

Almost surely, 2^77972000221 is an apocalyptic number.

It is an amenable number.

77972000221 is a deficient number, since it is larger than the sum of its proper divisors (1).

77972000221 is an equidigital number, since it uses as much as digits as its factorization.

77972000221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24696, while the sum is 37.

The spelling of 77972000221 in words is "seventy-seven billion, nine hundred seventy-two million, two hundred twenty-one", and thus it is an aban number.