1978239381 has 16 divisors (see below), whose sum is σ = 2764829760. Its totient is φ = 1256734080.

The previous prime is 1978239377. The next prime is 1978239413. The reversal of 1978239381 is 1839328791.

It is not a de Polignac number, because 1978239381 - 2² = 1978239377 is a prime.

It is a super-2 number, since 2×1978239381² = 7826862097078526322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978239331) 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 15 ways as a sum of consecutive naturals, for example, 181726 + ... + 192303.

It is an arithmetic number, because the mean of its divisors is an integer number (172801860).

Almost surely, 2^1978239381 is an apocalyptic number.

It is an amenable number.

1978239381 is a deficient number, since it is larger than the sum of its proper divisors (786590379).

1978239381 is a wasteful number, since it uses less digits than its factorization.

1978239381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374116.

The product of its digits is 653184, while the sum is 51.

The square root of 1978239381 is about 44477.4030379473. The cubic root of 1978239381 is about 1255.3349330125.

The spelling of 1978239381 in words is "one billion, nine hundred seventy-eight million, two hundred thirty-nine thousand, three hundred eighty-one".