1798397891 has 2 divisors, whose sum is σ = 1798397892. Its totient is φ = 1798397890.

The previous prime is 1798397873. The next prime is 1798397897. The reversal of 1798397891 is 1987938971.

It is a strong prime.

It is an emirp because it is prime and its reverse (1987938971) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1798397891 is a prime.

It is not a weakly prime, because it can be changed into another prime (1798397897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 899198945 + 899198946.

It is an arithmetic number, because the mean of its divisors is an integer number (899198946).

Almost surely, 2^1798397891 is an apocalyptic number.

1798397891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1798397891 is an equidigital number, since it uses as much as digits as its factorization.

1798397891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6858432, while the sum is 62.

The square root of 1798397891 is about 42407.5216323708. The cubic root of 1798397891 is about 1216.0793901144.

The spelling of 1798397891 in words is "one billion, seven hundred ninety-eight million, three hundred ninety-seven thousand, eight hundred ninety-one".