1978688957 has 16 divisors (see below), whose sum is σ = 2302523520. Its totient is φ = 1665309888.

The previous prime is 1978688947. The next prime is 1978688963. The reversal of 1978688957 is 7598868791.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978688957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978688917) 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 15 ways as a sum of consecutive naturals, for example, 142019 + ... + 155327.

It is an arithmetic number, because the mean of its divisors is an integer number (143907720).

Almost surely, 2^1978688957 is an apocalyptic number.

It is an amenable number.

1978688957 is a deficient number, since it is larger than the sum of its proper divisors (323834563).

1978688957 is a wasteful number, since it uses less digits than its factorization.

1978688957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13700.

The product of its digits is 60963840, while the sum is 68.

The square root of 1978688957 is about 44482.4567329638. The cubic root of 1978688957 is about 1255.4300218941.

The spelling of 1978688957 in words is "one billion, nine hundred seventy-eight million, six hundred eighty-eight thousand, nine hundred fifty-seven".