11921978 has 8 divisors (see below), whose sum is σ = 17907168. Its totient is φ = 5952924.

The previous prime is 11921977. The next prime is 11921989. The reversal of 11921978 is 87912911.

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

It is not an unprimeable number, because it can be changed into a prime (11921977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1976 + ... + 5267.

It is an arithmetic number, because the mean of its divisors is an integer number (2238396).

Almost surely, 2^11921978 is an apocalyptic number.

11921978 is a deficient number, since it is larger than the sum of its proper divisors (5985190).

11921978 is an equidigital number, since it uses as much as digits as its factorization.

11921978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8068.

The product of its digits is 9072, while the sum is 38.

The square root of 11921978 is about 3452.8217446025. The cubic root of 11921978 is about 228.4455864956.

The spelling of 11921978 in words is "eleven million, nine hundred twenty-one thousand, nine hundred seventy-eight".