21841491 has 8 divisors (see below), whose sum is σ = 33282304. Its totient is φ = 12480840.

The previous prime is 21841489. The next prime is 21841537. The reversal of 21841491 is 19414812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21841491 - 2¹ = 21841489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21841441) 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, 520015 + ... + 520056.

It is an arithmetic number, because the mean of its divisors is an integer number (4160288).

Almost surely, 2^21841491 is an apocalyptic number.

21841491 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21841491 is a deficient number, since it is larger than the sum of its proper divisors (11440813).

21841491 is a wasteful number, since it uses less digits than its factorization.

21841491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040081.

The product of its digits is 2304, while the sum is 30.

The square root of 21841491 is about 4673.4880977702. The cubic root of 21841491 is about 279.5293581680.

The spelling of 21841491 in words is "twenty-one million, eight hundred forty-one thousand, four hundred ninety-one".