1161256021 has 2 divisors, whose sum is σ = 1161256022. Its totient is φ = 1161256020.

The previous prime is 1161256007. The next prime is 1161256067. The reversal of 1161256021 is 1206521611.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1139062500 + 22193521 = 33750^2 + 4711^2 .

It is a cyclic number.

It is not a de Polignac number, because 1161256021 - 2¹⁵ = 1161223253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1161256081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 580628010 + 580628011.

It is an arithmetic number, because the mean of its divisors is an integer number (580628011).

Almost surely, 2^1161256021 is an apocalyptic number.

It is an amenable number.

1161256021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1161256021 is an equidigital number, since it uses as much as digits as its factorization.

1161256021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 1161256021 is about 34077.2067664003. The cubic root of 1161256021 is about 1051.0966685512.

Adding to 1161256021 its reverse (1206521611), we get a palindrome (2367777632).

The spelling of 1161256021 in words is "one billion, one hundred sixty-one million, two hundred fifty-six thousand, twenty-one".