11991651 has 8 divisors (see below), whose sum is σ = 18273024. Its totient is φ = 6852360.

The previous prime is 11991643. The next prime is 11991659. The reversal of 11991651 is 15619911.

It is an interprime number because it is at equal distance from previous prime (11991643) and next prime (11991659).

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

It is not a de Polignac number, because 11991651 - 2³ = 11991643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11991659) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 285495 + ... + 285536.

It is an arithmetic number, because the mean of its divisors is an integer number (2284128).

Almost surely, 2^11991651 is an apocalyptic number.

11991651 is a deficient number, since it is larger than the sum of its proper divisors (6281373).

11991651 is an equidigital number, since it uses as much as digits as its factorization.

11991651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 571041.

The product of its digits is 2430, while the sum is 33.

The square root of 11991651 is about 3462.8963311078. The cubic root of 11991651 is about 228.8897405299.

It can be divided in two parts, 1199 and 1651, that added together give a triangular number (2850 = T₇₅).

The spelling of 11991651 in words is "eleven million, nine hundred ninety-one thousand, six hundred fifty-one".