648773891 has 2 divisors, whose sum is σ = 648773892. Its totient is φ = 648773890.

The previous prime is 648773837. The next prime is 648773893. The reversal of 648773891 is 198377846.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-648773891 is a prime.

Together with 648773893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (648773893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324386945 + 324386946.

It is an arithmetic number, because the mean of its divisors is an integer number (324386946).

Almost surely, 2^648773891 is an apocalyptic number.

648773891 is a deficient number, since it is larger than the sum of its proper divisors (1).

648773891 is an equidigital number, since it uses as much as digits as its factorization.

648773891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2032128, while the sum is 53.

The square root of 648773891 is about 25471.0402418119. The cubic root of 648773891 is about 865.6940940143.

The spelling of 648773891 in words is "six hundred forty-eight million, seven hundred seventy-three thousand, eight hundred ninety-one".