16561373 has 4 divisors (see below), whose sum is σ = 16624608. Its totient is φ = 16498140.

The previous prime is 16561367. The next prime is 16561379. The reversal of 16561373 is 37316561.

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, and also an emirpimes, since its reverse is a distinct semiprime: 37316561 = 43 ⋅867827.

It is an interprime number because it is at equal distance from previous prime (16561367) and next prime (16561379).

It is a cyclic number.

It is not a de Polignac number, because 16561373 - 2⁶ = 16561309 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 (16561379) 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, 31223 + ... + 31748.

It is an arithmetic number, because the mean of its divisors is an integer number (4156152).

Almost surely, 2^16561373 is an apocalyptic number.

It is an amenable number.

16561373 is a deficient number, since it is larger than the sum of its proper divisors (63235).

16561373 is an equidigital number, since it uses as much as digits as its factorization.

16561373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63234.

The product of its digits is 11340, while the sum is 32.

The square root of 16561373 is about 4069.5666845501. The cubic root of 16561373 is about 254.8974238208.

The spelling of 16561373 in words is "sixteen million, five hundred sixty-one thousand, three hundred seventy-three".