1971647 has 2 divisors, whose sum is σ = 1971648. Its totient is φ = 1971646.

The previous prime is 1971637. The next prime is 1971659. The reversal of 1971647 is 7461791.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1971647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1971637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 985823 + 985824.

It is an arithmetic number, because the mean of its divisors is an integer number (985824).

2^1971647 is an apocalyptic number.

1971647 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971647 is an equidigital number, since it uses as much as digits as its factorization.

1971647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 35.

The square root of 1971647 is about 1404.1534816394. The cubic root of 1971647 is about 125.3938934797.

The spelling of 1971647 in words is "one million, nine hundred seventy-one thousand, six hundred forty-seven".