649878919 has 2 divisors, whose sum is σ = 649878920. Its totient is φ = 649878918.

The previous prime is 649878899. The next prime is 649878937. The reversal of 649878919 is 919878946.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 649878919 - 2²¹ = 647781767 is a prime.

It is a super-2 number, since 2×649878919² = 844685218721217122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649878949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324939459 + 324939460.

It is an arithmetic number, because the mean of its divisors is an integer number (324939460).

Almost surely, 2^649878919 is an apocalyptic number.

649878919 is a deficient number, since it is larger than the sum of its proper divisors (1).

649878919 is an equidigital number, since it uses as much as digits as its factorization.

649878919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7838208, while the sum is 61.

The square root of 649878919 is about 25492.7228635938. The cubic root of 649878919 is about 866.1853147715.

The spelling of 649878919 in words is "six hundred forty-nine million, eight hundred seventy-eight thousand, nine hundred nineteen".