9717981 has 16 divisors (see below), whose sum is σ = 15947904. Its totient is φ = 5125824.

The previous prime is 9717977. The next prime is 9717989. The reversal of 9717981 is 1897179.

It is a happy number.

It is not a de Polignac number, because 9717981 - 2² = 9717977 is a prime.

It is a super-2 number, since 2×9717981² = 188878309432722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9717989) 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 in 15 ways as a sum of consecutive naturals, for example, 17526 + ... + 18071.

It is an arithmetic number, because the mean of its divisors is an integer number (996744).

Almost surely, 2^9717981 is an apocalyptic number.

9717981 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

9717981 is a deficient number, since it is larger than the sum of its proper divisors (6229923).

9717981 is a wasteful number, since it uses less digits than its factorization.

9717981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35620.

The product of its digits is 31752, while the sum is 42.

The square root of 9717981 is about 3117.3676395318. The cubic root of 9717981 is about 213.3988207697.

The spelling of 9717981 in words is "nine million, seven hundred seventeen thousand, nine hundred eighty-one".