20619990 has 48 divisors (see below), whose sum is σ = 53930448. Its totient is φ = 5466048.

The previous prime is 20619979. The next prime is 20620003. The reversal of 20619990 is 9991602.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 17149 + ... + 18311.

It is an arithmetic number, because the mean of its divisors is an integer number (1123551).

Almost surely, 2^20619990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20619990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26965224).

20619990 is an abundant number, since it is smaller than the sum of its proper divisors (33310458).

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

20619990 is a wasteful number, since it uses less digits than its factorization.

20619990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373 (or 1370 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 20619990 is about 4540.9239147997. The cubic root of 20619990 is about 274.2181206672.

It can be divided in two parts, 20619 and 990, that added together give a square (21609 = 147²).

The spelling of 20619990 in words is "twenty million, six hundred nineteen thousand, nine hundred ninety".