21103007 has 4 divisors (see below), whose sum is σ = 21169896. Its totient is φ = 21036120.

The previous prime is 21103003. The next prime is 21103021. The reversal of 21103007 is 70030112.

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

It is not a de Polignac number, because 21103007 - 2² = 21103003 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21102982 and 21103000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103003) 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, 32969 + ... + 33602.

It is an arithmetic number, because the mean of its divisors is an integer number (5292474).

Almost surely, 2^21103007 is an apocalyptic number.

21103007 is a deficient number, since it is larger than the sum of its proper divisors (66889).

21103007 is an equidigital number, since it uses as much as digits as its factorization.

21103007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66888.

The product of its (nonzero) digits is 42, while the sum is 14.

The square root of 21103007 is about 4593.8009316904. The cubic root of 21103007 is about 276.3427749516.

Adding to 21103007 its reverse (70030112), we get a palindrome (91133119).

The spelling of 21103007 in words is "twenty-one million, one hundred three thousand, seven".