21741020 has 48 divisors (see below), whose sum is σ = 52835328. Its totient is φ = 7360320.

The previous prime is 21741019. The next prime is 21741023. The reversal of 21741020 is 2014712.

It is a self number, because there is not a number n which added to its sum of digits gives 21741020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21741023) 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, 10685 + ... + 12555.

It is an arithmetic number, because the mean of its divisors is an integer number (1100736).

Almost surely, 2^21741020 is an apocalyptic number.

21741020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21741020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26417664).

21741020 is an abundant number, since it is smaller than the sum of its proper divisors (31094308).

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

21741020 is a wasteful number, since it uses less digits than its factorization.

21741020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1970 (or 1968 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21741020 is about 4662.7266700934. The cubic root of 21741020 is about 279.1000869911.

Adding to 21741020 its reverse (2014712), we get a palindrome (23755732).

The spelling of 21741020 in words is "twenty-one million, seven hundred forty-one thousand, twenty".