21003699 has 4 divisors (see below), whose sum is σ = 28004936. Its totient is φ = 14002464.

The previous prime is 21003677. The next prime is 21003707. The reversal of 21003699 is 99630012.

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

It is not a de Polignac number, because 21003699 - 2⁵ = 21003667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003659) 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 3 ways as a sum of consecutive naturals, for example, 3500614 + ... + 3500619.

It is an arithmetic number, because the mean of its divisors is an integer number (7001234).

Almost surely, 2^21003699 is an apocalyptic number.

21003699 is a deficient number, since it is larger than the sum of its proper divisors (7001237).

21003699 is an equidigital number, since it uses as much as digits as its factorization.

21003699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7001236.

The product of its (nonzero) digits is 2916, while the sum is 30.

The square root of 21003699 is about 4582.9792711728. The cubic root of 21003699 is about 275.9086155133.

The spelling of 21003699 in words is "twenty-one million, three thousand, six hundred ninety-nine".