16511221541 has 8 divisors (see below), whose sum is σ = 16903127064. Its totient is φ = 16123795200.

The previous prime is 16511221477. The next prime is 16511221579. The reversal of 16511221541 is 14512211561.

It can be written as a sum of positive squares in 4 ways, for example, as 5851485025 + 10659736516 = 76495^2 + 103246^2 .

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 16511221541 - 2⁶ = 16511221477 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 (16511221591) 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, 1112336 + ... + 1127081.

It is an arithmetic number, because the mean of its divisors is an integer number (2112890883).

Almost surely, 2^16511221541 is an apocalyptic number.

It is an amenable number.

16511221541 is a deficient number, since it is larger than the sum of its proper divisors (391905523).

16511221541 is a wasteful number, since it uses less digits than its factorization.

16511221541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2239591.

The product of its digits is 2400, while the sum is 29.

The spelling of 16511221541 in words is "sixteen billion, five hundred eleven million, two hundred twenty-one thousand, five hundred forty-one".