1971478637 has 2 divisors, whose sum is σ = 1971478638. Its totient is φ = 1971478636.

The previous prime is 1971478601. The next prime is 1971478657. The reversal of 1971478637 is 7368741791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1338754921 + 632723716 = 36589^2 + 25154^2 .

It is a cyclic number.

It is not a de Polignac number, because 1971478637 - 2¹⁸ = 1971216493 is a prime.

It is a super-2 number, since 2×1971478637² = 7773456032294755538, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1971478657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 985739318 + 985739319.

It is an arithmetic number, because the mean of its divisors is an integer number (985739319).

Almost surely, 2^1971478637 is an apocalyptic number.

It is an amenable number.

1971478637 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971478637 is an equidigital number, since it uses as much as digits as its factorization.

1971478637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1778112, while the sum is 53.

The square root of 1971478637 is about 44401.3359821526. The cubic root of 1971478637 is about 1253.9032416375.

The spelling of 1971478637 in words is "one billion, nine hundred seventy-one million, four hundred seventy-eight thousand, six hundred thirty-seven".