1971210917 has 16 divisors (see below), whose sum is σ = 2239104000. Its totient is φ = 1720315584.

The previous prime is 1971210889. The next prime is 1971210947. The reversal of 1971210917 is 7190121791.

It is a de Polignac number, because none of the positive numbers 2^k-1971210917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1971210947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 117884 + ... + 133562.

It is an arithmetic number, because the mean of its divisors is an integer number (139944000).

Almost surely, 2^1971210917 is an apocalyptic number.

It is an amenable number.

1971210917 is a deficient number, since it is larger than the sum of its proper divisors (267893083).

1971210917 is a wasteful number, since it uses less digits than its factorization.

1971210917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16220.

The product of its (nonzero) digits is 7938, while the sum is 38.

The square root of 1971210917 is about 44398.3211056454. The cubic root of 1971210917 is about 1253.8464804894.

The spelling of 1971210917 in words is "one billion, nine hundred seventy-one million, two hundred ten thousand, nine hundred seventeen".