1971478657 has 2 divisors, whose sum is σ = 1971478658. Its totient is φ = 1971478656.

The previous prime is 1971478637. The next prime is 1971478669. The reversal of 1971478657 is 7568741791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1654781041 + 316697616 = 40679^2 + 17796^2 .

It is a cyclic number.

It is not a de Polignac number, because 1971478657 - 2⁷ = 1971478529 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1971478598 and 1971478607.

It is not a weakly prime, because it can be changed into another prime (1971478637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 985739328 + 985739329.

It is an arithmetic number, because the mean of its divisors is an integer number (985739329).

Almost surely, 2^1971478657 is an apocalyptic number.

It is an amenable number.

1971478657 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971478657 is an equidigital number, since it uses as much as digits as its factorization.

1971478657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2963520, while the sum is 55.

The square root of 1971478657 is about 44401.3362073711. The cubic root of 1971478657 is about 1253.9032458776.

The spelling of 1971478657 in words is "one billion, nine hundred seventy-one million, four hundred seventy-eight thousand, six hundred fifty-seven".