1288192421 has 2 divisors, whose sum is σ = 1288192422. Its totient is φ = 1288192420.

The previous prime is 1288192417. The next prime is 1288192501. The reversal of 1288192421 is 1242918821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1189905025 + 98287396 = 34495^2 + 9914^2 .

It is a cyclic number.

It is not a de Polignac number, because 1288192421 - 2² = 1288192417 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1288192621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 644096210 + 644096211.

It is an arithmetic number, because the mean of its divisors is an integer number (644096211).

Almost surely, 2^1288192421 is an apocalyptic number.

It is an amenable number.

1288192421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1288192421 is an equidigital number, since it uses as much as digits as its factorization.

1288192421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 38.

The square root of 1288192421 is about 35891.3975905091. The cubic root of 1288192421 is about 1088.0785442526.

The spelling of 1288192421 in words is "one billion, two hundred eighty-eight million, one hundred ninety-two thousand, four hundred twenty-one".