21478603 has 4 divisors (see below), whose sum is σ = 21521808. Its totient is φ = 21435400.

The previous prime is 21478579. The next prime is 21478627. The reversal of 21478603 is 30687412.

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

It is an interprime number because it is at equal distance from previous prime (21478579) and next prime (21478627).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21478603 is a prime.

It is a super-2 number, since 2×21478603² = 922660773663218, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21478663) 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, 20848 + ... + 21853.

It is an arithmetic number, because the mean of its divisors is an integer number (5380452).

Almost surely, 2^21478603 is an apocalyptic number.

21478603 is a deficient number, since it is larger than the sum of its proper divisors (43205).

21478603 is an equidigital number, since it uses as much as digits as its factorization.

21478603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43204.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21478603 is about 4634.5013755527. The cubic root of 21478603 is about 277.9726134538.

The spelling of 21478603 in words is "twenty-one million, four hundred seventy-eight thousand, six hundred three".