11721988 has 12 divisors (see below), whose sum is σ = 20950272. Its totient is φ = 5736200.

The previous prime is 11721971. The next prime is 11721991. The reversal of 11721988 is 88912711.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30988 + ... + 31363.

It is an arithmetic number, because the mean of its divisors is an integer number (1745856).

Almost surely, 2^11721988 is an apocalyptic number.

It is an amenable number.

11721988 is a deficient number, since it is larger than the sum of its proper divisors (9228284).

11721988 is a wasteful number, since it uses less digits than its factorization.

11721988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62402 (or 62400 counting only the distinct ones).

The product of its digits is 8064, while the sum is 37.

The square root of 11721988 is about 3423.7388919133. The cubic root of 11721988 is about 227.1609924850.

It can be divided in two parts, 1172 and 1988, that added together give a triangular number (3160 = T₇₉).

The spelling of 11721988 in words is "eleven million, seven hundred twenty-one thousand, nine hundred eighty-eight".