1978391212 has 12 divisors (see below), whose sum is σ = 3956782480. Its totient is φ = 847881936.

The previous prime is 1978391203. The next prime is 1978391243. The reversal of 1978391212 is 2121938791.

1978391212 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35328387 + ... + 35328442.

Almost surely, 2^1978391212 is an apocalyptic number.

It is an amenable number.

1978391212 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1978391212 is a wasteful number, since it uses less digits than its factorization.

1978391212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70656840 (or 70656838 counting only the distinct ones).

The product of its digits is 54432, while the sum is 43.

The square root of 1978391212 is about 44479.1098382151. The cubic root of 1978391212 is about 1255.3670480815.

The spelling of 1978391212 in words is "one billion, nine hundred seventy-eight million, three hundred ninety-one thousand, two hundred twelve".