2172780902561 has 2 divisors, whose sum is σ = 2172780902562. Its totient is φ = 2172780902560.

The previous prime is 2172780902497. The next prime is 2172780902603. The reversal of 2172780902561 is 1652090872712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1335041593600 + 837739308961 = 1155440^2 + 915281^2 .

It is a cyclic number.

It is not a de Polignac number, because 2172780902561 - 2⁶ = 2172780902497 is a prime.

It is not a weakly prime, because it can be changed into another prime (2172780902261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1086390451280 + 1086390451281.

It is an arithmetic number, because the mean of its divisors is an integer number (1086390451281).

Almost surely, 2^{2172780902561} is an apocalyptic number.

It is an amenable number.

2172780902561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2172780902561 is an equidigital number, since it uses as much as digits as its factorization.

2172780902561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 846720, while the sum is 50.

The spelling of 2172780902561 in words is "two trillion, one hundred seventy-two billion, seven hundred eighty million, nine hundred two thousand, five hundred sixty-one".