21441491 has 4 divisors (see below), whose sum is σ = 22133184. Its totient is φ = 20749800.

The previous prime is 21441467. The next prime is 21441493. The reversal of 21441491 is 19414412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21441491 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21441491.

It is not an unprimeable number, because it can be changed into a prime (21441493) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345800 + ... + 345861.

It is an arithmetic number, because the mean of its divisors is an integer number (5533296).

Almost surely, 2^21441491 is an apocalyptic number.

21441491 is a deficient number, since it is larger than the sum of its proper divisors (691693).

21441491 is an equidigital number, since it uses as much as digits as its factorization.

21441491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691692.

The product of its digits is 1152, while the sum is 26.

The square root of 21441491 is about 4630.4957617948. The cubic root of 21441491 is about 277.8124219842.

The spelling of 21441491 in words is "twenty-one million, four hundred forty-one thousand, four hundred ninety-one".