11721611 has 4 divisors (see below), whose sum is σ = 12787224. Its totient is φ = 10656000.

The previous prime is 11721607. The next prime is 11721623. The reversal of 11721611 is 11612711.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 11721611 - 2² = 11721607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11721691) 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, 532790 + ... + 532811.

It is an arithmetic number, because the mean of its divisors is an integer number (3196806).

Almost surely, 2^11721611 is an apocalyptic number.

11721611 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

11721611 is a deficient number, since it is larger than the sum of its proper divisors (1065613).

11721611 is a wasteful number, since it uses less digits than its factorization.

11721611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1065612.

The product of its digits is 84, while the sum is 20.

The square root of 11721611 is about 3423.6838347020. The cubic root of 11721611 is about 227.1585571582.

Subtracting from 11721611 its reverse (11612711), we obtain a square (108900 = 330²).

The spelling of 11721611 in words is "eleven million, seven hundred twenty-one thousand, six hundred eleven".