1978133644 has 12 divisors (see below), whose sum is σ = 3542239624. Its totient is φ = 966065184.

The previous prime is 1978133639. The next prime is 1978133713. The reversal of 1978133644 is 4463318791.

It is a junction number, because it is equal to n+sod(n) for n = 1978133594 and 1978133603.

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 3 ways as a sum of consecutive naturals, for example, 5750217 + ... + 5750560.

Almost surely, 2^1978133644 is an apocalyptic number.

It is an amenable number.

1978133644 is a deficient number, since it is larger than the sum of its proper divisors (1564105980).

1978133644 is a wasteful number, since it uses less digits than its factorization.

1978133644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11500824 (or 11500822 counting only the distinct ones).

The product of its digits is 435456, while the sum is 46.

The square root of 1978133644 is about 44476.2143622858. The cubic root of 1978133644 is about 1255.3125667078.

The spelling of 1978133644 in words is "one billion, nine hundred seventy-eight million, one hundred thirty-three thousand, six hundred forty-four".