20019090 has 64 divisors (see below), whose sum is σ = 59141376. Its totient is φ = 4223232.

The previous prime is 20019073. The next prime is 20019091. The reversal of 20019090 is 9091002.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (20019091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 937 + ... + 6396.

It is an arithmetic number, because the mean of its divisors is an integer number (924084).

Almost surely, 2^20019090 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20019090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29570688).

20019090 is an abundant number, since it is smaller than the sum of its proper divisors (39122286).

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

20019090 is a wasteful number, since it uses less digits than its factorization.

20019090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7363.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 20019090 is about 4474.2697728233. The cubic root of 20019090 is about 271.5280979165.

The spelling of 20019090 in words is "twenty million, nineteen thousand, ninety".