21503413 has 16 divisors (see below), whose sum is σ = 23512320. Its totient is φ = 19603584.

The previous prime is 21503399. The next prime is 21503423. The reversal of 21503413 is 31430512.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21503413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21503423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68545 + ... + 68857.

It is an arithmetic number, because the mean of its divisors is an integer number (1469520).

Almost surely, 2^21503413 is an apocalyptic number.

21503413 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21503413 is a deficient number, since it is larger than the sum of its proper divisors (2008907).

21503413 is a wasteful number, since it uses less digits than its factorization.

21503413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21503413 is about 4637.1772663982. The cubic root of 21503413 is about 278.0796012757.

Adding to 21503413 its reverse (31430512), we get a palindrome (52933925).

The spelling of 21503413 in words is "twenty-one million, five hundred three thousand, four hundred thirteen".