668019539 has 16 divisors (see below), whose sum is σ = 776272896. Its totient is φ = 568118400.

The previous prime is 668019533. The next prime is 668019557. The reversal of 668019539 is 935910866.

It is a cyclic number.

It is not a de Polignac number, because 668019539 - 2⁴ = 668019523 is a prime.

It is a Duffinian number.

668019539 is a modest number, since divided by 19539 gives 668 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 668019493 and 668019502.

It is not an unprimeable number, because it can be changed into a prime (668019533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20534 + ... + 41924.

It is an arithmetic number, because the mean of its divisors is an integer number (48517056).

Almost surely, 2^668019539 is an apocalyptic number.

668019539 is a deficient number, since it is larger than the sum of its proper divisors (108253357).

668019539 is a wasteful number, since it uses less digits than its factorization.

668019539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21586.

The product of its (nonzero) digits is 349920, while the sum is 47.

The square root of 668019539 is about 25846.0739571796. The cubic root of 668019539 is about 874.1709868866.

The spelling of 668019539 in words is "six hundred sixty-eight million, nineteen thousand, five hundred thirty-nine".