21409246 has 4 divisors (see below), whose sum is σ = 32113872. Its totient is φ = 10704622.

The previous prime is 21409243. The next prime is 21409249. The reversal of 21409246 is 64290412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21409243) and next prime (21409249).

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21409243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5352310 + ... + 5352313.

It is an arithmetic number, because the mean of its divisors is an integer number (8028468).

Almost surely, 2^21409246 is an apocalyptic number.

21409246 is a deficient number, since it is larger than the sum of its proper divisors (10704626).

21409246 is a wasteful number, since it uses less digits than its factorization.

21409246 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10704625.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21409246 is about 4627.0126431641. The cubic root of 21409246 is about 277.6730884547.

Adding to 21409246 its reverse (64290412), we get a palindrome (85699658).

The spelling of 21409246 in words is "twenty-one million, four hundred nine thousand, two hundred forty-six".