65981643 has 16 divisors (see below), whose sum is σ = 108278016. Its totient is φ = 34803360.

The previous prime is 65981633. The next prime is 65981653. The reversal of 65981643 is 34618956.

It is an interprime number because it is at equal distance from previous prime (65981633) and next prime (65981653).

It is not a de Polignac number, because 65981643 - 2⁴ = 65981627 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 65981595 and 65981604.

It is not an unprimeable number, because it can be changed into a prime (65981633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 120573 + ... + 121118.

It is an arithmetic number, because the mean of its divisors is an integer number (6767376).

Almost surely, 2^65981643 is an apocalyptic number.

65981643 is a deficient number, since it is larger than the sum of its proper divisors (42296373).

65981643 is a wasteful number, since it uses less digits than its factorization.

65981643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241714.

The product of its digits is 155520, while the sum is 42.

The square root of 65981643 is about 8122.9085308158. The cubic root of 65981643 is about 404.0865313946.

The spelling of 65981643 in words is "sixty-five million, nine hundred eighty-one thousand, six hundred forty-three".