1978786197 has 6 divisors (see below), whose sum is σ = 2858246742. Its totient is φ = 1319190792.

The previous prime is 1978786181. The next prime is 1978786207. The reversal of 1978786197 is 7916878791.

1978786197 is a `hidden beast` number, since 1 + 9 + 7 + 8 + 7 + 8 + 619 + 7 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1586508561 + 392277636 = 39831^2 + 19806^2 .

It is not a de Polignac number, because 1978786197 - 2⁴ = 1978786181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978786127) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109932558 + ... + 109932575.

It is an arithmetic number, because the mean of its divisors is an integer number (476374457).

Almost surely, 2^1978786197 is an apocalyptic number.

It is an amenable number.

1978786197 is a deficient number, since it is larger than the sum of its proper divisors (879460545).

1978786197 is a wasteful number, since it uses less digits than its factorization.

1978786197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219865139 (or 219865136 counting only the distinct ones).

The product of its digits is 10668672, while the sum is 63.

The square root of 1978786197 is about 44483.5497347053. The cubic root of 1978786197 is about 1255.4505870289.

The spelling of 1978786197 in words is "one billion, nine hundred seventy-eight million, seven hundred eighty-six thousand, one hundred ninety-seven".