16501421533 has 4 divisors (see below), whose sum is σ = 16502557500. Its totient is φ = 16500285568.

The previous prime is 16501421509. The next prime is 16501421537. The reversal of 16501421533 is 33512410561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2454905209 + 14046516324 = 49547^2 + 118518^2 .

It is a cyclic number.

It is not a de Polignac number, because 16501421533 - 2¹⁷ = 16501290461 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16501421495 and 16501421504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16501421537) 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, 545908 + ... + 575341.

It is an arithmetic number, because the mean of its divisors is an integer number (4125639375).

Almost surely, 2^16501421533 is an apocalyptic number.

It is an amenable number.

16501421533 is a deficient number, since it is larger than the sum of its proper divisors (1135967).

16501421533 is a wasteful number, since it uses less digits than its factorization.

16501421533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1135966.

The product of its (nonzero) digits is 10800, while the sum is 31.

The spelling of 16501421533 in words is "sixteen billion, five hundred one million, four hundred twenty-one thousand, five hundred thirty-three".