97729981 has 4 divisors (see below), whose sum is σ = 97848700. Its totient is φ = 97611264.

The previous prime is 97729979. The next prime is 97729993. The reversal of 97729981 is 18992779.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 41344900 + 56385081 = 6430^2 + 7509^2 .

It is a cyclic number.

It is not a de Polignac number, because 97729981 - 2¹ = 97729979 is a prime.

It is a super-2 number, since 2×97729981² = 19102298372520722, 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 (97729781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58116 + ... + 59773.

It is an arithmetic number, because the mean of its divisors is an integer number (24462175).

Almost surely, 2^97729981 is an apocalyptic number.

It is an amenable number.

97729981 is a deficient number, since it is larger than the sum of its proper divisors (118719).

97729981 is a wasteful number, since it uses less digits than its factorization.

97729981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118718.

The product of its digits is 571536, while the sum is 52.

The square root of 97729981 is about 9885.8475104566. The cubic root of 97729981 is about 460.6198025013.

The spelling of 97729981 in words is "ninety-seven million, seven hundred twenty-nine thousand, nine hundred eighty-one".