21741491 has 8 divisors (see below), whose sum is σ = 22948800. Its totient is φ = 20540520.

The previous prime is 21741481. The next prime is 21741493. The reversal of 21741491 is 19414712.

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

It is a de Polignac number, because none of the positive numbers 2^k-21741491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21741493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6596 + ... + 9326.

It is an arithmetic number, because the mean of its divisors is an integer number (2868600).

Almost surely, 2^21741491 is an apocalyptic number.

21741491 is a deficient number, since it is larger than the sum of its proper divisors (1207309).

21741491 is a wasteful number, since it uses less digits than its factorization.

21741491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3169.

The product of its digits is 2016, while the sum is 29.

The square root of 21741491 is about 4662.7771767478. Note that the first 3 decimals coincide. The cubic root of 21741491 is about 279.1021024622.

The spelling of 21741491 in words is "twenty-one million, seven hundred forty-one thousand, four hundred ninety-one".