11897561 has 4 divisors (see below), whose sum is σ = 12812772. Its totient is φ = 10982352.

The previous prime is 11897549. The next prime is 11897573. The reversal of 11897561 is 16579811.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (11897549) and next prime (11897573).

It can be written as a sum of positive squares in 2 ways, for example, as 3400336 + 8497225 = 1844^2 + 2915^2 .

It is a cyclic number.

It is not a de Polignac number, because 11897561 - 2¹⁰ = 11896537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11897531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 457586 + ... + 457611.

It is an arithmetic number, because the mean of its divisors is an integer number (3203193).

Almost surely, 2^11897561 is an apocalyptic number.

It is an amenable number.

11897561 is a deficient number, since it is larger than the sum of its proper divisors (915211).

11897561 is an equidigital number, since it uses as much as digits as its factorization.

11897561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915210.

The product of its digits is 15120, while the sum is 38.

The square root of 11897561 is about 3449.2841286273. The cubic root of 11897561 is about 228.2895226771.

It can be divided in two parts, 118 and 97561, that added together give a palindrome (97679).

The spelling of 11897561 in words is "eleven million, eight hundred ninety-seven thousand, five hundred sixty-one".