1978999980 has 24 divisors (see below), whose sum is σ = 5541200112. Its totient is φ = 527733312.

The previous prime is 1978999961. The next prime is 1978999987. The reversal of 1978999980 is 899998791.

It is not an unprimeable number, because it can be changed into a prime (1978999987) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 16491607 + ... + 16491726.

It is an arithmetic number, because the mean of its divisors is an integer number (230883338).

Almost surely, 2^1978999980 is an apocalyptic number.

1978999980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1978999980 is an abundant number, since it is smaller than the sum of its proper divisors (3562200132).

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

1978999980 is a wasteful number, since it uses less digits than its factorization.

1978999980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32983345 (or 32983343 counting only the distinct ones).

The product of its (nonzero) digits is 26453952, while the sum is 69.

The square root of 1978999980 is about 44485.9526142804. The cubic root of 1978999980 is about 1255.4957972910.

The spelling of 1978999980 in words is "one billion, nine hundred seventy-eight million, nine hundred ninety-nine thousand, nine hundred eighty".