16617539021 has 4 divisors (see below), whose sum is σ = 16772843232. Its totient is φ = 16462234812.

The previous prime is 16617539011. The next prime is 16617539063. The reversal of 16617539021 is 12093571661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12093571661 = 431 ⋅28059331.

It is a cyclic number.

It is not a de Polignac number, because 16617539021 - 2¹⁴ = 16617522637 is a prime.

It is a super-2 number, since 2×16617539021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16617539021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16617539011) 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, 77651945 + ... + 77652158.

It is an arithmetic number, because the mean of its divisors is an integer number (4193210808).

Almost surely, 2^16617539021 is an apocalyptic number.

It is an amenable number.

16617539021 is a deficient number, since it is larger than the sum of its proper divisors (155304211).

16617539021 is a wasteful number, since it uses less digits than its factorization.

16617539021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155304210.

The product of its (nonzero) digits is 68040, while the sum is 41.

The spelling of 16617539021 in words is "sixteen billion, six hundred seventeen million, five hundred thirty-nine thousand, twenty-one".