16812021861 has 12 divisors (see below), whose sum is σ = 24534383692. Its totient is φ = 11092467456.

The previous prime is 16812021859. The next prime is 16812021899.

16812021861 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 5714452836 + 11097569025 = 75594^2 + 105345^2 .

It is not a de Polignac number, because 16812021861 - 2¹ = 16812021859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16812022861) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9628006 + ... + 9629751.

Almost surely, 2^16812021861 is an apocalyptic number.

It is an amenable number.

16812021861 is a deficient number, since it is larger than the sum of its proper divisors (7722361831).

16812021861 is a wasteful number, since it uses less digits than its factorization.

16812021861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19257860 (or 19257857 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

It can be divided in two parts, 168120 and 21861, that added together give a palindrome (189981).

The spelling of 16812021861 in words is "sixteen billion, eight hundred twelve million, twenty-one thousand, eight hundred sixty-one".