1996978021 has 8 divisors (see below), whose sum is σ = 2074500288. Its totient is φ = 1920828000.

The previous prime is 1996978003. The next prime is 1996978031. The reversal of 1996978021 is 1208796991.

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

It is a cyclic number.

It is not a de Polignac number, because 1996978021 - 2⁵ = 1996977989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1996978021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1996978001) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 340095 + ... + 345916.

It is an arithmetic number, because the mean of its divisors is an integer number (259312536).

Almost surely, 2^1996978021 is an apocalyptic number.

It is an amenable number.

1996978021 is a deficient number, since it is larger than the sum of its proper divisors (77522267).

1996978021 is an equidigital number, since it uses as much as digits as its factorization.

1996978021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686123.

The product of its (nonzero) digits is 489888, while the sum is 52.

The square root of 1996978021 is about 44687.5600251345. The cubic root of 1996978021 is about 1259.2861541881.

The spelling of 1996978021 in words is "one billion, nine hundred ninety-six million, nine hundred seventy-eight thousand, twenty-one".