1978890920 has 16 divisors (see below), whose sum is σ = 4452504660. Its totient is φ = 791556352.

The previous prime is 1978890877. The next prime is 1978890923. The reversal of 1978890920 is 290988791.

It can be written as a sum of positive squares in 2 ways, for example, as 1947103876 + 31787044 = 44126^2 + 5638^2 .

It is not an unprimeable number, because it can be changed into a prime (1978890923) 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 3 ways as a sum of consecutive naturals, for example, 24736097 + ... + 24736176.

Almost surely, 2^1978890920 is an apocalyptic number.

1978890920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1978890920 is an abundant number, since it is smaller than the sum of its proper divisors (2473613740).

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

1978890920 is a wasteful number, since it uses less digits than its factorization.

1978890920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49472284 (or 49472280 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 53.

The square root of 1978890920 is about 44484.7268171897. The cubic root of 1978890920 is about 1255.4727339782.

The spelling of 1978890920 in words is "one billion, nine hundred seventy-eight million, eight hundred ninety thousand, nine hundred twenty".