97831981 has 8 divisors (see below), whose sum is σ = 105489944. Its totient is φ = 90192960.

The previous prime is 97831967. The next prime is 97832003. The reversal of 97831981 is 18913879.

It can be written as a sum of positive squares in 4 ways, for example, as 100 + 97831881 = 10^2 + 9891^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 97831981 - 2⁹ = 97831469 is a prime.

It is a super-2 number, since 2×97831981² = 19142193012768722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (97831901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7111 + ... + 15691.

It is an arithmetic number, because the mean of its divisors is an integer number (13186243).

Almost surely, 2^97831981 is an apocalyptic number.

It is an amenable number.

97831981 is a deficient number, since it is larger than the sum of its proper divisors (7657963).

97831981 is a wasteful number, since it uses less digits than its factorization.

97831981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9471.

The product of its digits is 108864, while the sum is 46.

The square root of 97831981 is about 9891.0050550993. The cubic root of 97831981 is about 460.7799951856.

The spelling of 97831981 in words is "ninety-seven million, eight hundred thirty-one thousand, nine hundred eighty-one".