19993890 has 64 divisors (see below), whose sum is σ = 57738240. Its totient is φ = 4328640.

The previous prime is 19993889. The next prime is 19993891. The reversal of 19993890 is 9839991.

It is an interprime number because it is at equal distance from previous prime (19993889) and next prime (19993891).

It is not an unprimeable number, because it can be changed into a prime (19993891) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1485 + ... + 6495.

It is an arithmetic number, because the mean of its divisors is an integer number (902160).

Almost surely, 2^19993890 is an apocalyptic number.

19993890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 19993890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28869120).

19993890 is an abundant number, since it is smaller than the sum of its proper divisors (37744350).

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

19993890 is a wasteful number, since it uses less digits than its factorization.

19993890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5047.

The product of its (nonzero) digits is 157464, while the sum is 48.

The square root of 19993890 is about 4471.4527840513. The cubic root of 19993890 is about 271.4141170248.

It can be divided in two parts, 199938 and 90, that added together give a triangular number (200028 = T₆₃₂).

The spelling of 19993890 in words is "nineteen million, nine hundred ninety-three thousand, eight hundred ninety".