10643981 has 2 divisors, whose sum is σ = 10643982. Its totient is φ = 10643980.

The previous prime is 10643939. The next prime is 10644001. The reversal of 10643981 is 18934601.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6375625 + 4268356 = 2525^2 + 2066^2 .

It is a cyclic number.

It is not a de Polignac number, because 10643981 - 2¹⁴ = 10627597 is a prime.

It is a super-2 number, since 2×10643981² = 226588663056722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10643081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5321990 + 5321991.

It is an arithmetic number, because the mean of its divisors is an integer number (5321991).

Almost surely, 2^10643981 is an apocalyptic number.

It is an amenable number.

10643981 is a deficient number, since it is larger than the sum of its proper divisors (1).

10643981 is an equidigital number, since it uses as much as digits as its factorization.

10643981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 10643981 is about 3262.5114559186. The cubic root of 10643981 is about 219.9723174535.

The spelling of 10643981 in words is "ten million, six hundred forty-three thousand, nine hundred eighty-one".