16505123653 has 4 divisors (see below), whose sum is σ = 16566481260. Its totient is φ = 16443766048.

The previous prime is 16505123639. The next prime is 16505123671. The reversal of 16505123653 is 35632150561.

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 376631649 + 16128492004 = 19407^2 + 126998^2 .

It is a cyclic number.

It is not a de Polignac number, because 16505123653 - 2²⁵ = 16471569221 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 (16505123153) 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, 30678400 + ... + 30678937.

It is an arithmetic number, because the mean of its divisors is an integer number (4141620315).

Almost surely, 2^16505123653 is an apocalyptic number.

It is an amenable number.

16505123653 is a deficient number, since it is larger than the sum of its proper divisors (61357607).

16505123653 is an equidigital number, since it uses as much as digits as its factorization.

16505123653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61357606.

The product of its (nonzero) digits is 81000, while the sum is 37.

The spelling of 16505123653 in words is "sixteen billion, five hundred five million, one hundred twenty-three thousand, six hundred fifty-three".