16561207 has 4 divisors (see below), whose sum is σ = 17835160. Its totient is φ = 15287256.

The previous prime is 16561189. The next prime is 16561211. The reversal of 16561207 is 70216561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70216561 = 281 ⋅249881.

It is a cyclic number.

It is not a de Polignac number, because 16561207 - 2⁷ = 16561079 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 (16561277) 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, 636957 + ... + 636982.

It is an arithmetic number, because the mean of its divisors is an integer number (4458790).

Almost surely, 2^16561207 is an apocalyptic number.

16561207 is a deficient number, since it is larger than the sum of its proper divisors (1273953).

16561207 is a wasteful number, since it uses less digits than its factorization.

16561207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1273952.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 16561207 is about 4069.5462892072. The cubic root of 16561207 is about 254.8965721782.

Adding to 16561207 its reverse (70216561), we get a palindrome (86777768).

The spelling of 16561207 in words is "sixteen million, five hundred sixty-one thousand, two hundred seven".