1188591421 has 2 divisors, whose sum is σ = 1188591422. Its totient is φ = 1188591420.

The previous prime is 1188591347. The next prime is 1188591449. The reversal of 1188591421 is 1241958811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 963171225 + 225420196 = 31035^2 + 15014^2 .

It is an emirp because it is prime and its reverse (1241958811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1188591421 - 2¹¹ = 1188589373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1188591451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594295710 + 594295711.

It is an arithmetic number, because the mean of its divisors is an integer number (594295711).

Almost surely, 2^1188591421 is an apocalyptic number.

It is an amenable number.

1188591421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1188591421 is an equidigital number, since it uses as much as digits as its factorization.

1188591421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23040, while the sum is 40.

The square root of 1188591421 is about 34475.9542435014. The cubic root of 1188591421 is about 1059.2802224633.

The spelling of 1188591421 in words is "one billion, one hundred eighty-eight million, five hundred ninety-one thousand, four hundred twenty-one".