21541065 has 64 divisors (see below), whose sum is σ = 43524096. Its totient is φ = 8854272.

The previous prime is 21541061. The next prime is 21541097. The reversal of 21541065 is 56014512.

It is not a de Polignac number, because 21541065 - 2² = 21541061 is a prime.

It is a super-5 number, since 5×21541065⁵ (a number of 38 digits) contains 55555 as substring.

It is not an unprimeable number, because it can be changed into a prime (21541061) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 58512 + ... + 58878.

It is an arithmetic number, because the mean of its divisors is an integer number (680064).

Almost surely, 2^21541065 is an apocalyptic number.

It is an amenable number.

21541065 is an abundant number, since it is smaller than the sum of its proper divisors (21983031).

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

21541065 is a wasteful number, since it uses less digits than its factorization.

21541065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 21541065 is about 4641.2352881534. The cubic root of 21541065 is about 278.2418103790.

Adding to 21541065 its reverse (56014512), we get a palindrome (77555577).

The spelling of 21541065 in words is "twenty-one million, five hundred forty-one thousand, sixty-five".