11971399731 has 8 divisors (see below), whose sum is σ = 15964262544. Its totient is φ = 7979735040.

The previous prime is 11971399729. The next prime is 11971399747. The reversal of 11971399731 is 13799317911.

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

It is not a de Polignac number, because 11971399731 - 2¹ = 11971399729 is a prime.

It is a super-2 number, since 2×11971399731² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (11971399771) 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, 275950 + ... + 316371.

It is an arithmetic number, because the mean of its divisors is an integer number (1995532818).

Almost surely, 2^11971399731 is an apocalyptic number.

11971399731 is a deficient number, since it is larger than the sum of its proper divisors (3992862813).

11971399731 is an equidigital number, since it uses as much as digits as its factorization.

11971399731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599061.

The product of its digits is 321489, while the sum is 51.

The spelling of 11971399731 in words is "eleven billion, nine hundred seventy-one million, three hundred ninety-nine thousand, seven hundred thirty-one".