684369881 has 4 divisors (see below), whose sum is σ = 737013732. Its totient is φ = 631726032.

The previous prime is 684369863. The next prime is 684369887. The reversal of 684369881 is 188963486.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 188963486 = 2 ⋅94481743.

It can be written as a sum of positive squares in 2 ways, for example, as 251064025 + 433305856 = 15845^2 + 20816^2 .

It is a cyclic number.

It is not a de Polignac number, because 684369881 - 2¹⁰ = 684368857 is a prime.

It is a super-2 number, since 2×684369881² = 936724268039908322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (684369887) 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, 26321906 + ... + 26321931.

It is an arithmetic number, because the mean of its divisors is an integer number (184253433).

Almost surely, 2^684369881 is an apocalyptic number.

It is an amenable number.

684369881 is a deficient number, since it is larger than the sum of its proper divisors (52643851).

684369881 is a wasteful number, since it uses less digits than its factorization.

684369881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52643850.

The product of its digits is 1990656, while the sum is 53.

The square root of 684369881 is about 26160.4640822750. The cubic root of 684369881 is about 881.2456022046.

The spelling of 684369881 in words is "six hundred eighty-four million, three hundred sixty-nine thousand, eight hundred eighty-one".