21541020 has 24 divisors (see below), whose sum is σ = 60315024. Its totient is φ = 5744256.

The previous prime is 21541019. The next prime is 21541021. The reversal of 21541020 is 2014512.

It is an interprime number because it is at equal distance from previous prime (21541019) and next prime (21541021).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179449 + ... + 179568.

It is an arithmetic number, because the mean of its divisors is an integer number (2513126).

Almost surely, 2^21541020 is an apocalyptic number.

21541020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21541020 is an abundant number, since it is smaller than the sum of its proper divisors (38774004).

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

21541020 is a wasteful number, since it uses less digits than its factorization.

21541020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359029 (or 359027 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21541020 is about 4641.2304403035. The cubic root of 21541020 is about 278.2416166268.

Adding to 21541020 its reverse (2014512), we get a palindrome (23555532).

The spelling of 21541020 in words is "twenty-one million, five hundred forty-one thousand, twenty".