2621111261 has 2 divisors, whose sum is σ = 2621111262. Its totient is φ = 2621111260.

The previous prime is 2621111243. The next prime is 2621111267. The reversal of 2621111261 is 1621111262.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1658932900 + 962178361 = 40730^2 + 31019^2 .

It is a cyclic number.

It is not a de Polignac number, because 2621111261 - 2¹⁰ = 2621110237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2621111267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1310555630 + 1310555631.

It is an arithmetic number, because the mean of its divisors is an integer number (1310555631).

Almost surely, 2^2621111261 is an apocalyptic number.

It is an amenable number.

2621111261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2621111261 is an equidigital number, since it uses as much as digits as its factorization.

2621111261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 23.

The square root of 2621111261 is about 51196.7895575494. The cubic root of 2621111261 is about 1378.7805619465.

Subtracting from 2621111261 its reverse (1621111262), we obtain a palindrome (999999999).

The spelling of 2621111261 in words is "two billion, six hundred twenty-one million, one hundred eleven thousand, two hundred sixty-one".