1990647678 has 8 divisors (see below), whose sum is σ = 3981295368. Its totient is φ = 663549224.

The previous prime is 1990647643. The next prime is 1990647679. The reversal of 1990647678 is 8767460991.

It is a sphenic number, since it is the product of 3 distinct primes.

1990647678 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990647679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165887301 + ... + 165887312.

It is an arithmetic number, because the mean of its divisors is an integer number (497661921).

Almost surely, 2^1990647678 is an apocalyptic number.

1990647678 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.

1990647678 is a wasteful number, since it uses less digits than its factorization.

1990647678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 331774618.

The product of its (nonzero) digits is 4572288, while the sum is 57.

The square root of 1990647678 is about 44616.6748873109. The cubic root of 1990647678 is about 1257.9541162431.

The spelling of 1990647678 in words is "one billion, nine hundred ninety million, six hundred forty-seven thousand, six hundred seventy-eight".