21741321 has 8 divisors (see below), whose sum is σ = 33129664. Its totient is φ = 12423600.

The previous prime is 21741319. The next prime is 21741337. The reversal of 21741321 is 12314712.

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

It is not a de Polignac number, because 21741321 - 2¹ = 21741319 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1035301 = 21741321 / (2 + 1 + 7 + 4 + 1 + 3 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21741341) 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, 517630 + ... + 517671.

It is an arithmetic number, because the mean of its divisors is an integer number (4141208).

Almost surely, 2^21741321 is an apocalyptic number.

21741321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21741321 is a deficient number, since it is larger than the sum of its proper divisors (11388343).

21741321 is a wasteful number, since it uses less digits than its factorization.

21741321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035311.

The product of its digits is 336, while the sum is 21.

The square root of 21741321 is about 4662.7589472329. The cubic root of 21741321 is about 279.1013750132.

21741321 divided by its sum of digits (21) gives a palindrome (1035301).

The spelling of 21741321 in words is "twenty-one million, seven hundred forty-one thousand, three hundred twenty-one".