19990866 has 16 divisors (see below), whose sum is σ = 45693504. Its totient is φ = 5711664.

The previous prime is 19990849. The next prime is 19990879. The reversal of 19990866 is 66809991.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 237945 + ... + 238028.

It is an arithmetic number, because the mean of its divisors is an integer number (2855844).

Almost surely, 2^19990866 is an apocalyptic number.

19990866 is an abundant number, since it is smaller than the sum of its proper divisors (25702638).

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

19990866 is a wasteful number, since it uses less digits than its factorization.

19990866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475985.

The product of its (nonzero) digits is 209952, while the sum is 48.

The square root of 19990866 is about 4471.1146261307. The cubic root of 19990866 is about 271.4004328831.

The spelling of 19990866 in words is "nineteen million, nine hundred ninety thousand, eight hundred sixty-six".