172771227721 has 2 divisors, whose sum is σ = 172771227722. Its totient is φ = 172771227720.

The previous prime is 172771227677. The next prime is 172771227767. The reversal of 172771227721 is 127722177271.

It is an a-pointer prime, because the next prime (172771227767) can be obtained adding 172771227721 to its sum of digits (46).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138375816121 + 34395411600 = 371989^2 + 185460^2 .

It is a cyclic number.

It is not a de Polignac number, because 172771227721 - 2¹⁷ = 172771096649 is a prime.

It is not a weakly prime, because it can be changed into another prime (172771227781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86385613860 + 86385613861.

It is an arithmetic number, because the mean of its divisors is an integer number (86385613861).

Almost surely, 2^172771227721 is an apocalyptic number.

It is an amenable number.

172771227721 is a deficient number, since it is larger than the sum of its proper divisors (1).

172771227721 is an equidigital number, since it uses as much as digits as its factorization.

172771227721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 268912, while the sum is 46.

The spelling of 172771227721 in words is "one hundred seventy-two billion, seven hundred seventy-one million, two hundred twenty-seven thousand, seven hundred twenty-one".