1978139634 has 16 divisors (see below), whose sum is σ = 3956752800. Its totient is φ = 659300960.

The previous prime is 1978139599. The next prime is 1978139663. The reversal of 1978139634 is 4369318791.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58342 + ... + 85790.

It is an arithmetic number, because the mean of its divisors is an integer number (247297050).

Almost surely, 2^1978139634 is an apocalyptic number.

1978139634 is an abundant number, since it is smaller than the sum of its proper divisors (1978613166).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1978139634 is a wasteful number, since it uses less digits than its factorization.

1978139634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39465.

The product of its digits is 979776, while the sum is 51.

The square root of 1978139634 is about 44476.2817015991. The cubic root of 1978139634 is about 1255.3138337800.

The spelling of 1978139634 in words is "one billion, nine hundred seventy-eight million, one hundred thirty-nine thousand, six hundred thirty-four".