21423513 has 8 divisors (see below), whose sum is σ = 28602688. Its totient is φ = 14263344.

The previous prime is 21423509. The next prime is 21423527. The reversal of 21423513 is 31532412.

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

It is not a de Polignac number, because 21423513 - 2² = 21423509 is a prime.

It is a super-2 number, since 2×21423513² = 917933818522338, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21423513.

It is not an unprimeable number, because it can be changed into a prime (21423533) 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, 1870 + ... + 6807.

It is an arithmetic number, because the mean of its divisors is an integer number (3575336).

Almost surely, 2^21423513 is an apocalyptic number.

It is an amenable number.

21423513 is a deficient number, since it is larger than the sum of its proper divisors (7179175).

21423513 is an equidigital number, since it uses as much as digits as its factorization.

21423513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9503.

The product of its digits is 720, while the sum is 21.

The square root of 21423513 is about 4628.5540938829. The cubic root of 21423513 is about 277.7347546820.

Adding to 21423513 its reverse (31532412), we get a palindrome (52955925).

The spelling of 21423513 in words is "twenty-one million, four hundred twenty-three thousand, five hundred thirteen".