101781002261 has 2 divisors, whose sum is σ = 101781002262. Its totient is φ = 101781002260.

The previous prime is 101781002227. The next prime is 101781002269. The reversal of 101781002261 is 162200187101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 99662701636 + 2118300625 = 315694^2 + 46025^2 .

It is an emirp because it is prime and its reverse (162200187101) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 101781002261 - 2¹⁰ = 101781001237 is a prime.

It is a super-2 number, since 2×101781002261² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101781002269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50890501130 + 50890501131.

It is an arithmetic number, because the mean of its divisors is an integer number (50890501131).

Almost surely, 2^101781002261 is an apocalyptic number.

It is an amenable number.

101781002261 is a deficient number, since it is larger than the sum of its proper divisors (1).

101781002261 is an equidigital number, since it uses as much as digits as its factorization.

101781002261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 29.

Adding to 101781002261 its reverse (162200187101), we get a palindrome (263981189362).

The spelling of 101781002261 in words is "one hundred one billion, seven hundred eighty-one million, two thousand, two hundred sixty-one".