16661243501 has 4 divisors (see below), whose sum is σ = 19041421152. Its totient is φ = 14281065852.

The previous prime is 16661243483. The next prime is 16661243519. The reversal of 16661243501 is 10534216661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (16661243483) and next prime (16661243519).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16661243501 is a prime.

It is a super-2 number, since 2×16661243501² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16661243801) 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, 1190088815 + ... + 1190088828.

It is an arithmetic number, because the mean of its divisors is an integer number (4760355288).

Almost surely, 2^16661243501 is an apocalyptic number.

It is an amenable number.

16661243501 is a deficient number, since it is larger than the sum of its proper divisors (2380177651).

16661243501 is an equidigital number, since it uses as much as digits as its factorization.

16661243501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2380177650.

The product of its (nonzero) digits is 25920, while the sum is 35.

The spelling of 16661243501 in words is "sixteen billion, six hundred sixty-one million, two hundred forty-three thousand, five hundred one".