21431003 has 4 divisors (see below), whose sum is σ = 23379288. Its totient is φ = 19482720.

The previous prime is 21430991. The next prime is 21431017. The reversal of 21431003 is 30013412.

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

It is a cyclic number.

It is not a de Polignac number, because 21431003 - 2¹² = 21426907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21431023) 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, 974126 + ... + 974147.

It is an arithmetic number, because the mean of its divisors is an integer number (5844822).

Almost surely, 2^21431003 is an apocalyptic number.

21431003 is a deficient number, since it is larger than the sum of its proper divisors (1948285).

21431003 is a wasteful number, since it uses less digits than its factorization.

21431003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1948284.

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

The square root of 21431003 is about 4629.3631311445. The cubic root of 21431003 is about 277.7671177361.

Adding to 21431003 its reverse (30013412), we get a palindrome (51444415).

The spelling of 21431003 in words is "twenty-one million, four hundred thirty-one thousand, three".