11991570 has 16 divisors (see below), whose sum is σ = 28779840. Its totient is φ = 3197744.

The previous prime is 11991523. The next prime is 11991583. The reversal of 11991570 is 7519911.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 199830 + ... + 199889.

It is an arithmetic number, because the mean of its divisors is an integer number (1798740).

Almost surely, 2^11991570 is an apocalyptic number.

11991570 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

11991570 is an abundant number, since it is smaller than the sum of its proper divisors (16788270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11991570 is a wasteful number, since it uses less digits than its factorization.

11991570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399729.

The product of its (nonzero) digits is 2835, while the sum is 33.

The square root of 11991570 is about 3462.8846356759. The cubic root of 11991570 is about 228.8892251682.

It can be divided in two parts, 11991 and 570, that added together give a triangular number (12561 = T₁₅₈).

The spelling of 11991570 in words is "eleven million, nine hundred ninety-one thousand, five hundred seventy".