1990635406 has 4 divisors (see below), whose sum is σ = 2985953112. Its totient is φ = 995317702.

The previous prime is 1990635359. The next prime is 1990635431. The reversal of 1990635406 is 6045360991.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 497658850 + ... + 497658853.

It is an arithmetic number, because the mean of its divisors is an integer number (746488278).

Almost surely, 2^1990635406 is an apocalyptic number.

1990635406 is a deficient number, since it is larger than the sum of its proper divisors (995317706).

1990635406 is an equidigital number, since it uses as much as digits as its factorization.

1990635406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995317705.

The product of its (nonzero) digits is 174960, while the sum is 43.

The square root of 1990635406 is about 44616.5373600417. The cubic root of 1990635406 is about 1257.9515312144.

The spelling of 1990635406 in words is "one billion, nine hundred ninety million, six hundred thirty-five thousand, four hundred six".