21620003 has 2 divisors, whose sum is σ = 21620004. Its totient is φ = 21620002.

The previous prime is 21619991. The next prime is 21620017. The reversal of 21620003 is 30002612.

It is an a-pointer prime, because the next prime (21620017) can be obtained adding 21620003 to its sum of digits (14).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21620003 - 2¹² = 21615907 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21620003.

It is not a weakly prime, because it can be changed into another prime (21620063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810001 + 10810002.

It is an arithmetic number, because the mean of its divisors is an integer number (10810002).

Almost surely, 2^21620003 is an apocalyptic number.

21620003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620003 is an equidigital number, since it uses as much as digits as its factorization.

21620003 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21620003 is about 4649.7314976244. The cubic root of 21620003 is about 278.5812717351.

Adding to 21620003 its reverse (30002612), we get a palindrome (51622615).

The spelling of 21620003 in words is "twenty-one million, six hundred twenty thousand, three".