21956126978 has 8 divisors (see below), whose sum is σ = 32936099472. Its totient is φ = 10977427156.

The previous prime is 21956126963. The next prime is 21956126981. The reversal of 21956126978 is 87962165912.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 273800 + ... + 344787.

It is an arithmetic number, because the mean of its divisors is an integer number (4117012434).

Almost surely, 2^21956126978 is an apocalyptic number.

21956126978 is a deficient number, since it is larger than the sum of its proper divisors (10979972494).

21956126978 is a wasteful number, since it uses less digits than its factorization.

21956126978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636336.

The product of its digits is 3265920, while the sum is 56.

The spelling of 21956126978 in words is "twenty-one billion, nine hundred fifty-six million, one hundred twenty-six thousand, nine hundred seventy-eight".