20891442 has 48 divisors (see below), whose sum is σ = 49383648. Its totient is φ = 5840640.

The previous prime is 20891413. The next prime is 20891443. The reversal of 20891442 is 24419802.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20891443) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10218 + ... + 12090.

It is an arithmetic number, because the mean of its divisors is an integer number (1028826).

Almost surely, 2^20891442 is an apocalyptic number.

20891442 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 20891442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24691824).

20891442 is an abundant number, since it is smaller than the sum of its proper divisors (28492206).

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

20891442 is a wasteful number, since it uses less digits than its factorization.

20891442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1915 (or 1902 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 20891442 is about 4570.7156988813. The cubic root of 20891442 is about 275.4161940429.

The spelling of 20891442 in words is "twenty million, eight hundred ninety-one thousand, four hundred forty-two".