16191990 has 96 divisors (see below), whose sum is σ = 47005920. Its totient is φ = 3843072.

The previous prime is 16191961. The next prime is 16191997. The reversal of 16191990 is 9919161.

Added to its reverse (9919161) it gives a triangular number (26111151 = T₇₂₂₆).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16191997) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 28792 + ... + 29348.

It is an arithmetic number, because the mean of its divisors is an integer number (489645).

Almost surely, 2^16191990 is an apocalyptic number.

16191990 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 16191990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23502960).

16191990 is an abundant number, since it is smaller than the sum of its proper divisors (30813930).

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

16191990 is a wasteful number, since it uses less digits than its factorization.

16191990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606 (or 603 counting only the distinct ones).

The product of its (nonzero) digits is 4374, while the sum is 36.

The square root of 16191990 is about 4023.9271862199. The cubic root of 16191990 is about 252.9880896558.

Adding to 16191990 its reverse (9919161), we get a triangular number (26111151 = T₇₂₂₆).

The spelling of 16191990 in words is "sixteen million, one hundred ninety-one thousand, nine hundred ninety".