9979781 has 6 divisors (see below), whose sum is σ = 11609190. Its totient is φ = 8554056.

The previous prime is 9979777. The next prime is 9979789. The reversal of 9979781 is 1879799.

It can be written as a sum of positive squares in only one way, i.e., 9060100 + 919681 = 3010^2 + 959^2 .

It is not a de Polignac number, because 9979781 - 2² = 9979777 is a prime.

It is a super-2 number, since 2×9979781² = 199192057615922, 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 (9979789) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 101786 + ... + 101883.

It is an arithmetic number, because the mean of its divisors is an integer number (1934865).

Almost surely, 2^9979781 is an apocalyptic number.

It is an amenable number.

9979781 is a deficient number, since it is larger than the sum of its proper divisors (1629409).

9979781 is a wasteful number, since it uses less digits than its factorization.

9979781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203683 (or 203676 counting only the distinct ones).

The product of its digits is 285768, while the sum is 50.

The square root of 9979781 is about 3159.0791379768. The cubic root of 9979781 is about 215.2981693153.

The spelling of 9979781 in words is "nine million, nine hundred seventy-nine thousand, seven hundred eighty-one".