921942978 has 64 divisors (see below), whose sum is σ = 2036828160. Its totient is φ = 275889600.

The previous prime is 921942961. The next prime is 921942991. The reversal of 921942978 is 879249129.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 921942978.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3328176 + ... + 3328452.

It is an arithmetic number, because the mean of its divisors is an integer number (31825440).

Almost surely, 2^921942978 is an apocalyptic number.

921942978 is an abundant number, since it is smaller than the sum of its proper divisors (1114885182).

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

921942978 is a wasteful number, since it uses less digits than its factorization.

921942978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 743.

The product of its digits is 653184, while the sum is 51.

The square root of 921942978 is about 30363.5139270803. The cubic root of 921942978 is about 973.2730254694.

The spelling of 921942978 in words is "nine hundred twenty-one million, nine hundred forty-two thousand, nine hundred seventy-eight".