648121819 has 2 divisors, whose sum is σ = 648121820. Its totient is φ = 648121818.

The previous prime is 648121811. The next prime is 648121829. The reversal of 648121819 is 918121846.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 648121819 - 2³ = 648121811 is a prime.

It is a super-2 number, since 2×648121819² = 840123784527737522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (648121811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324060909 + 324060910.

It is an arithmetic number, because the mean of its divisors is an integer number (324060910).

Almost surely, 2^648121819 is an apocalyptic number.

648121819 is a deficient number, since it is larger than the sum of its proper divisors (1).

648121819 is an equidigital number, since it uses as much as digits as its factorization.

648121819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 40.

The square root of 648121819 is about 25458.2367614099. The cubic root of 648121819 is about 865.4039651449.

The spelling of 648121819 in words is "six hundred forty-eight million, one hundred twenty-one thousand, eight hundred nineteen".