16561501065 has 96 divisors (see below), whose sum is σ = 30761482752. Its totient is φ = 8213760000.

The previous prime is 16561501027. The next prime is 16561501067. The reversal of 16561501065 is 56010516561.

It is not a de Polignac number, because 16561501065 - 2¹² = 16561496969 is a prime.

It is a super-2 number, since 2×16561501065² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16561501067) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 35924935 + ... + 35925395.

It is an arithmetic number, because the mean of its divisors is an integer number (320432112).

Almost surely, 2^16561501065 is an apocalyptic number.

16561501065 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16561501065 is a deficient number, since it is larger than the sum of its proper divisors (14199981687).

16561501065 is a wasteful number, since it uses less digits than its factorization.

16561501065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 951 (or 948 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 36.

The spelling of 16561501065 in words is "sixteen billion, five hundred sixty-one million, five hundred one thousand, sixty-five".