21395113179978 has 8 divisors (see below), whose sum is σ = 42790226359968. Its totient is φ = 7131704393324.

The previous prime is 21395113179971. The next prime is 21395113179983. The reversal of 21395113179978 is 87997131159312.

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

21395113179978 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21395113179971) 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, 1782926098326 + ... + 1782926098337.

It is an arithmetic number, because the mean of its divisors is an integer number (5348778294996).

Almost surely, 2^{21395113179978} is an apocalyptic number.

21395113179978 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21395113179978 is a wasteful number, since it uses less digits than its factorization.

21395113179978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3565852196668.

The product of its digits is 25719120, while the sum is 66.

The spelling of 21395113179978 in words is "twenty-one trillion, three hundred ninety-five billion, one hundred thirteen million, one hundred seventy-nine thousand, nine hundred seventy-eight".