11661555 has 8 divisors (see below), whose sum is σ = 18658512. Its totient is φ = 6219488.

The previous prime is 11661547. The next prime is 11661563. The reversal of 11661555 is 55516611.

It is an interprime number because it is at equal distance from previous prime (11661547) and next prime (11661563).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11661555 - 2³ = 11661547 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 388704 + ... + 388733.

It is an arithmetic number, because the mean of its divisors is an integer number (2332314).

Almost surely, 2^11661555 is an apocalyptic number.

11661555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

11661555 is a deficient number, since it is larger than the sum of its proper divisors (6996957).

11661555 is an equidigital number, since it uses as much as digits as its factorization.

11661555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777445.

The product of its digits is 4500, while the sum is 30.

The square root of 11661555 is about 3414.9019019585. The cubic root of 11661555 is about 226.7699416445.

The spelling of 11661555 in words is "eleven million, six hundred sixty-one thousand, five hundred fifty-five".