1188921389 has 2 divisors, whose sum is σ = 1188921390. Its totient is φ = 1188921388.

The previous prime is 1188921373. The next prime is 1188921427. The reversal of 1188921389 is 9831298811.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1180266025 + 8655364 = 34355^2 + 2942^2 .

It is a cyclic number.

It is not a de Polignac number, because 1188921389 - 2⁴ = 1188921373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1184921389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594460694 + 594460695.

It is an arithmetic number, because the mean of its divisors is an integer number (594460695).

Almost surely, 2^1188921389 is an apocalyptic number.

It is an amenable number.

1188921389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1188921389 is an equidigital number, since it uses as much as digits as its factorization.

1188921389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 50.

The square root of 1188921389 is about 34480.7393917242. The cubic root of 1188921389 is about 1059.3782365863.

The spelling of 1188921389 in words is "one billion, one hundred eighty-eight million, nine hundred twenty-one thousand, three hundred eighty-nine".