21162421 has 8 divisors (see below), whose sum is σ = 24223104. Its totient is φ = 18111120.

The previous prime is 21162403. The next prime is 21162439. The reversal of 21162421 is 12426112.

It is an interprime number because it is at equal distance from previous prime (21162403) and next prime (21162439).

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 21162421 - 2¹⁷ = 21031349 is a prime.

It is a super-3 number, since 3×21162421³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21162521) 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, 3456 + ... + 7366.

It is an arithmetic number, because the mean of its divisors is an integer number (3027888).

Almost surely, 2^21162421 is an apocalyptic number.

It is an amenable number.

21162421 is a deficient number, since it is larger than the sum of its proper divisors (3060683).

21162421 is an equidigital number, since it uses as much as digits as its factorization.

21162421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4691.

The product of its digits is 192, while the sum is 19.

The square root of 21162421 is about 4600.2631446473. The cubic root of 21162421 is about 276.6018730223.

Adding to 21162421 its reverse (12426112), we get a palindrome (33588533).

The spelling of 21162421 in words is "twenty-one million, one hundred sixty-two thousand, four hundred twenty-one".