16561949 has 4 divisors (see below), whose sum is σ = 16842720. Its totient is φ = 16281180.

The previous prime is 16561913. The next prime is 16561969. The reversal of 16561949 is 94916561.

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: 94916561 = 23 ⋅4126807.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16561949 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 (16561969) 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, 140297 + ... + 140414.

It is an arithmetic number, because the mean of its divisors is an integer number (4210680).

Almost surely, 2^16561949 is an apocalyptic number.

It is an amenable number.

16561949 is a deficient number, since it is larger than the sum of its proper divisors (280771).

16561949 is an equidigital number, since it uses as much as digits as its factorization.

16561949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280770.

The product of its digits is 58320, while the sum is 41.

The square root of 16561949 is about 4069.6374531400. The cubic root of 16561949 is about 254.9003788740.

The spelling of 16561949 in words is "sixteen million, five hundred sixty-one thousand, nine hundred forty-nine".