11971071720 has 48 divisors (see below), whose sum is σ = 38905984260. Its totient is φ = 3192285696.

The previous prime is 11971071677. The next prime is 11971071743. The reversal of 11971071720 is 2717017911.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 11939058756 + 32012964 = 109266^2 + 5658^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16626129 + ... + 16626848.

Almost surely, 2^11971071720 is an apocalyptic number.

11971071720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11971071720 is an abundant number, since it is smaller than the sum of its proper divisors (26934912540).

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

11971071720 is a wasteful number, since it uses less digits than its factorization.

11971071720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33252994 (or 33252987 counting only the distinct ones).

The product of its (nonzero) digits is 6174, while the sum is 36.

The spelling of 11971071720 in words is "eleven billion, nine hundred seventy-one million, seventy-one thousand, seven hundred twenty".