11990534978 has 4 divisors (see below), whose sum is σ = 17985802470. Its totient is φ = 5995267488.

The previous prime is 11990534971. The next prime is 11990535019. The reversal of 11990534978 is 87943509911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87943509911 = 3121 ⋅28177991.

It can be written as a sum of positive squares in only one way, i.e., 9353404369 + 2637130609 = 96713^2 + 51353^2 .

It is not an unprimeable number, because it can be changed into a prime (11990534971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2997633743 + ... + 2997633746.

Almost surely, 2^11990534978 is an apocalyptic number.

11990534978 is a deficient number, since it is larger than the sum of its proper divisors (5995267492).

11990534978 is an equidigital number, since it uses as much as digits as its factorization.

11990534978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5995267491.

The product of its (nonzero) digits is 2449440, while the sum is 56.

The spelling of 11990534978 in words is "eleven billion, nine hundred ninety million, five hundred thirty-four thousand, nine hundred seventy-eight".