20611990 has 32 divisors (see below), whose sum is σ = 44898624. Its totient is φ = 6650880.

The previous prime is 20611967. The next prime is 20611999. The reversal of 20611990 is 9911602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20611999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7471 + ... + 9850.

It is an arithmetic number, because the mean of its divisors is an integer number (1403082).

Almost surely, 2^20611990 is an apocalyptic number.

20611990 is an abundant number, since it is smaller than the sum of its proper divisors (24286634).

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

20611990 is a wasteful number, since it uses less digits than its factorization.

20611990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17352.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 20611990 is about 4540.0429513387. The cubic root of 20611990 is about 274.1826530016.

The spelling of 20611990 in words is "twenty million, six hundred eleven thousand, nine hundred ninety".