16881733921 has 8 divisors (see below), whose sum is σ = 18285419880. Its totient is φ = 15493060992.

The previous prime is 16881733919. The next prime is 16881733927. The reversal of 16881733921 is 12933718861.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3140033296 + 13741700625 = 56036^2 + 117225^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 16881733921 - 2¹ = 16881733919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16881733927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3750916 + ... + 3755413.

It is an arithmetic number, because the mean of its divisors is an integer number (2285677485).

Almost surely, 2^16881733921 is an apocalyptic number.

It is an amenable number.

16881733921 is a deficient number, since it is larger than the sum of its proper divisors (1403685959).

16881733921 is a wasteful number, since it uses less digits than its factorization.

16881733921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7506515.

The product of its digits is 435456, while the sum is 49.

The spelling of 16881733921 in words is "sixteen billion, eight hundred eighty-one million, seven hundred thirty-three thousand, nine hundred twenty-one".