9799999981 has 4 divisors (see below), whose sum is σ = 9806487264. Its totient is φ = 9793512700.

The previous prime is 9799999943. The next prime is 9799999997. The reversal of 9799999981 is 1899999979.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9799999981 is a prime.

It is a super-2 number, since 2×9799999981² (a number of 21 digits) 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 (9799999901) 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, 3241375 + ... + 3244396.

It is an arithmetic number, because the mean of its divisors is an integer number (2451621816).

Almost surely, 2^9799999981 is an apocalyptic number.

It is an amenable number.

9799999981 is a deficient number, since it is larger than the sum of its proper divisors (6487283).

9799999981 is a wasteful number, since it uses less digits than its factorization.

9799999981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6487282.

The product of its digits is 267846264, while the sum is 79.

The square root of 9799999981 is about 98994.9492701522. The cubic root of 9799999981 is about 2139.9749597472.

The spelling of 9799999981 in words is "nine billion, seven hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".