11391973521 has 8 divisors (see below), whose sum is σ = 15190896000. Its totient is φ = 7593850032.

The previous prime is 11391973499. The next prime is 11391973543. The reversal of 11391973521 is 12537919311.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (11391973499) and next prime (11391973543).

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

It is not a de Polignac number, because 11391973521 - 2⁶ = 11391973457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11391973561) 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, 165646 + ... + 224103.

It is an arithmetic number, because the mean of its divisors is an integer number (1898862000).

Almost surely, 2^11391973521 is an apocalyptic number.

It is an amenable number.

11391973521 is a deficient number, since it is larger than the sum of its proper divisors (3798922479).

11391973521 is an equidigital number, since it uses as much as digits as its factorization.

11391973521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399495.

The product of its digits is 51030, while the sum is 42.

The spelling of 11391973521 in words is "eleven billion, three hundred ninety-one million, nine hundred seventy-three thousand, five hundred twenty-one".