684946081 has 4 divisors (see below), whose sum is σ = 691230100. Its totient is φ = 678662064.

The previous prime is 684946057. The next prime is 684946091. The reversal of 684946081 is 180649486.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 180649486 = 2 ⋅90324743.

It can be written as a sum of positive squares in 2 ways, for example, as 402403600 + 282542481 = 20060^2 + 16809^2 .

It is a cyclic number.

It is not a de Polignac number, because 684946081 - 2¹³ = 684937889 is a prime.

It is a super-2 number, since 2×684946081² = 938302267754517122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684946091) 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, 3141846 + ... + 3142063.

It is an arithmetic number, because the mean of its divisors is an integer number (172807525).

Almost surely, 2^684946081 is an apocalyptic number.

It is an amenable number.

684946081 is a deficient number, since it is larger than the sum of its proper divisors (6284019).

684946081 is a wasteful number, since it uses less digits than its factorization.

684946081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6284018.

The product of its (nonzero) digits is 331776, while the sum is 46.

The square root of 684946081 is about 26171.4745667874. The cubic root of 684946081 is about 881.4928521647.

The spelling of 684946081 in words is "six hundred eighty-four million, nine hundred forty-six thousand, eighty-one".