16465643521 has 8 divisors (see below), whose sum is σ = 16998335744. Its totient is φ = 15933047760.

The previous prime is 16465643503. The next prime is 16465643567. The reversal of 16465643521 is 12534656461.

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 16465643521 - 2¹⁷ = 16465512449 is a prime.

It is a super-2 number, since 2×16465643521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16465643021) 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, 513070 + ... + 544216.

It is an arithmetic number, because the mean of its divisors is an integer number (2124791968).

Almost surely, 2^16465643521 is an apocalyptic number.

It is an amenable number.

16465643521 is a deficient number, since it is larger than the sum of its proper divisors (532692223).

16465643521 is a wasteful number, since it uses less digits than its factorization.

16465643521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48231.

The product of its digits is 518400, while the sum is 43.

The spelling of 16465643521 in words is "sixteen billion, four hundred sixty-five million, six hundred forty-three thousand, five hundred twenty-one".