21420841 has 8 divisors (see below), whose sum is σ = 23192064. Its totient is φ = 19667280.

The previous prime is 21420827. The next prime is 21420859. The reversal of 21420841 is 14802412.

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

It is a cyclic number.

It is not a de Polignac number, because 21420841 - 2⁷ = 21420713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1831 + ... + 6796.

It is an arithmetic number, because the mean of its divisors is an integer number (2899008).

Almost surely, 2^21420841 is an apocalyptic number.

It is an amenable number.

21420841 is a deficient number, since it is larger than the sum of its proper divisors (1771223).

21420841 is a wasteful number, since it uses less digits than its factorization.

21420841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8831.

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 21420841 is about 4628.2654418259. The cubic root of 21420841 is about 277.7232075854.

The spelling of 21420841 in words is "twenty-one million, four hundred twenty thousand, eight hundred forty-one".