2138421787 has 2 divisors, whose sum is σ = 2138421788. Its totient is φ = 2138421786.

The previous prime is 2138421751. The next prime is 2138421821. The reversal of 2138421787 is 7871248312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2138421787 is a prime.

It is not a weakly prime, because it can be changed into another prime (2138421587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1069210893 + 1069210894.

It is an arithmetic number, because the mean of its divisors is an integer number (1069210894).

Almost surely, 2^2138421787 is an apocalyptic number.

2138421787 is a deficient number, since it is larger than the sum of its proper divisors (1).

2138421787 is an equidigital number, since it uses as much as digits as its factorization.

2138421787 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150528, while the sum is 43.

The square root of 2138421787 is about 46243.0728542124. The cubic root of 2138421787 is about 1288.3418767876.

The spelling of 2138421787 in words is "two billion, one hundred thirty-eight million, four hundred twenty-one thousand, seven hundred eighty-seven".