1135981921 has 2 divisors, whose sum is σ = 1135981922. Its totient is φ = 1135981920.

The previous prime is 1135981919. The next prime is 1135981927. The reversal of 1135981921 is 1291895311.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 965966400 + 170015521 = 31080^2 + 13039^2 .

It is a cyclic number.

It is not a de Polignac number, because 1135981921 - 2¹ = 1135981919 is a prime.

Together with 1135981919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1135981927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 567990960 + 567990961.

It is an arithmetic number, because the mean of its divisors is an integer number (567990961).

Almost surely, 2^1135981921 is an apocalyptic number.

It is an amenable number.

1135981921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1135981921 is an equidigital number, since it uses as much as digits as its factorization.

1135981921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 40.

The square root of 1135981921 is about 33704.3308938184. The cubic root of 1135981921 is about 1043.4151540138.

The spelling of 1135981921 in words is "one billion, one hundred thirty-five million, nine hundred eighty-one thousand, nine hundred twenty-one".