21541091 has 16 divisors (see below), whose sum is σ = 26798688. Its totient is φ = 17011200.

The previous prime is 21541061. The next prime is 21541097. The reversal of 21541091 is 19014512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21541091 - 2⁶ = 21541027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21541097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2000 + ... + 6861.

It is an arithmetic number, because the mean of its divisors is an integer number (1674918).

Almost surely, 2^21541091 is an apocalyptic number.

21541091 is a deficient number, since it is larger than the sum of its proper divisors (5257597).

21541091 is a wasteful number, since it uses less digits than its factorization.

21541091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8902.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 21541091 is about 4641.2380891310. The cubic root of 21541091 is about 278.2419223246.

The spelling of 21541091 in words is "twenty-one million, five hundred forty-one thousand, ninety-one".