921572720161 has 2 divisors, whose sum is σ = 921572720162. Its totient is φ = 921572720160.

The previous prime is 921572720141. The next prime is 921572720281. The reversal of 921572720161 is 161027275129.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 874821631761 + 46751088400 = 935319^2 + 216220^2 .

It is a cyclic number.

It is not a de Polignac number, because 921572720161 - 2²⁹ = 921035849249 is a prime.

It is not a weakly prime, because it can be changed into another prime (921572720141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460786360080 + 460786360081.

It is an arithmetic number, because the mean of its divisors is an integer number (460786360081).

Almost surely, 2^921572720161 is an apocalyptic number.

It is an amenable number.

921572720161 is a deficient number, since it is larger than the sum of its proper divisors (1).

921572720161 is an equidigital number, since it uses as much as digits as its factorization.

921572720161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 43.

The spelling of 921572720161 in words is "nine hundred twenty-one billion, five hundred seventy-two million, seven hundred twenty thousand, one hundred sixty-one".