1978668529 has 8 divisors (see below), whose sum is σ = 2013768680. Its totient is φ = 1943654400.

The previous prime is 1978668479. The next prime is 1978668547. The reversal of 1978668529 is 9258668791.

It can be written as a sum of positive squares in 4 ways, for example, as 127690000 + 1850978529 = 11300^2 + 43023^2 .

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 1978668529 - 2⁷ = 1978668401 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (61).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978668229) 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, 25819 + ... + 67999.

It is an arithmetic number, because the mean of its divisors is an integer number (251721085).

Almost surely, 2^1978668529 is an apocalyptic number.

It is an amenable number.

1978668529 is a deficient number, since it is larger than the sum of its proper divisors (35100151).

1978668529 is an equidigital number, since it uses as much as digits as its factorization.

1978668529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43011.

The product of its digits is 13063680, while the sum is 61.

The square root of 1978668529 is about 44482.2271137586. The cubic root of 1978668529 is about 1255.4257015228.

The spelling of 1978668529 in words is "one billion, nine hundred seventy-eight million, six hundred sixty-eight thousand, five hundred twenty-nine".