649878157 has 2 divisors, whose sum is σ = 649878158. Its totient is φ = 649878156.

The previous prime is 649878143. The next prime is 649878161. The reversal of 649878157 is 751878946.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 545409316 + 104468841 = 23354^2 + 10221^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649878157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 649878098 and 649878107.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649878127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324939078 + 324939079.

It is an arithmetic number, because the mean of its divisors is an integer number (324939079).

Almost surely, 2^649878157 is an apocalyptic number.

It is an amenable number.

649878157 is a deficient number, since it is larger than the sum of its proper divisors (1).

649878157 is an equidigital number, since it uses as much as digits as its factorization.

649878157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3386880, while the sum is 55.

The square root of 649878157 is about 25492.7079181479. The cubic root of 649878157 is about 866.1849762297.

The spelling of 649878157 in words is "six hundred forty-nine million, eight hundred seventy-eight thousand, one hundred fifty-seven".