11211511261 has 2 divisors, whose sum is σ = 11211511262. Its totient is φ = 11211511260.

The previous prime is 11211511249. The next prime is 11211511307. The reversal of 11211511261 is 16211511211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9603020025 + 1608491236 = 97995^2 + 40106^2 .

It is a cyclic number.

It is not a de Polignac number, because 11211511261 - 2⁹ = 11211510749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11211581261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5605755630 + 5605755631.

It is an arithmetic number, because the mean of its divisors is an integer number (5605755631).

Almost surely, 2^11211511261 is an apocalyptic number.

It is an amenable number.

11211511261 is a deficient number, since it is larger than the sum of its proper divisors (1).

11211511261 is an equidigital number, since it uses as much as digits as its factorization.

11211511261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120, while the sum is 22.

The spelling of 11211511261 in words is "eleven billion, two hundred eleven million, five hundred eleven thousand, two hundred sixty-one".