21870003 has 4 divisors (see below), whose sum is σ = 29160008. Its totient is φ = 14580000.

The previous prime is 21869999. The next prime is 21870011. The reversal of 21870003 is 30007812.

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

It is not a de Polignac number, because 21870003 - 2² = 21869999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21870053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3644998 + ... + 3645003.

It is an arithmetic number, because the mean of its divisors is an integer number (7290002).

Almost surely, 2^21870003 is an apocalyptic number.

21870003 is a deficient number, since it is larger than the sum of its proper divisors (7290005).

21870003 is an equidigital number, since it uses as much as digits as its factorization.

21870003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7290004.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 21870003 is about 4676.5375011861. The cubic root of 21870003 is about 279.6509383228.

Adding to 21870003 its reverse (30007812), we get a palindrome (51877815).

The spelling of 21870003 in words is "twenty-one million, eight hundred seventy thousand, three".