1978139635 has 16 divisors (see below), whose sum is σ = 2520559296. Its totient is φ = 1485180928.

The previous prime is 1978139599. The next prime is 1978139663. The reversal of 1978139635 is 5369318791.

It is a happy number.

It is not a de Polignac number, because 1978139635 - 2²⁹ = 1441268723 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 2959 + ... + 62968.

It is an arithmetic number, because the mean of its divisors is an integer number (157534956).

Almost surely, 2^1978139635 is an apocalyptic number.

1978139635 is a deficient number, since it is larger than the sum of its proper divisors (542419661).

1978139635 is a wasteful number, since it uses less digits than its factorization.

1978139635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66302.

The product of its digits is 1224720, while the sum is 52.

The square root of 1978139635 is about 44476.2817128411. The cubic root of 1978139635 is about 1255.3138339915.

The spelling of 1978139635 in words is "one billion, nine hundred seventy-eight million, one hundred thirty-nine thousand, six hundred thirty-five".