1978855236 has 18 divisors (see below), whose sum is σ = 5002106382. Its totient is φ = 659618400.

The previous prime is 1978855213. The next prime is 1978855237. The reversal of 1978855236 is 6325588791.

1978855236 is a `hidden beast` number, since 1 + 9 + 7 + 88 + 552 + 3 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1944280836 + 34574400 = 44094^2 + 5880^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (1978855237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27484065 + ... + 27484136.

It is an arithmetic number, because the mean of its divisors is an integer number (277894799).

Almost surely, 2^1978855236 is an apocalyptic number.

It is an amenable number.

1978855236 is an abundant number, since it is smaller than the sum of its proper divisors (3023251146).

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

1978855236 is a wasteful number, since it uses less digits than its factorization.

1978855236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54968211 (or 54968206 counting only the distinct ones).

The product of its digits is 3628800, while the sum is 54.

The square root of 1978855236 is about 44484.3257339032. The cubic root of 1978855236 is about 1255.4651875696.

The spelling of 1978855236 in words is "one billion, nine hundred seventy-eight million, eight hundred fifty-five thousand, two hundred thirty-six".