21683181810394 has 8 divisors (see below), whose sum is σ = 35026678309140. Its totient is φ = 10007622374016.

The previous prime is 21683181810391. The next prime is 21683181810419. The reversal of 21683181810394 is 49301818138612.

It can be written as a sum of positive squares in 2 ways, for example, as 19321694966025 + 2361486844369 = 4395645^2 + 1536713^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21683181810391) 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, 416984265559 + ... + 416984265610.

Almost surely, 2^{21683181810394} is an apocalyptic number.

21683181810394 is a deficient number, since it is larger than the sum of its proper divisors (13343496498746).

21683181810394 is a wasteful number, since it uses less digits than its factorization.

21683181810394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 833968531184.

The product of its (nonzero) digits is 1990656, while the sum is 55.

The spelling of 21683181810394 in words is "twenty-one trillion, six hundred eighty-three billion, one hundred eighty-one million, eight hundred ten thousand, three hundred ninety-four".