21003143 has 8 divisors (see below), whose sum is σ = 25415712. Its totient is φ = 16943616.

The previous prime is 21003139. The next prime is 21003173. The reversal of 21003143 is 34130012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21003143 - 2² = 21003139 is a prime.

It is a super-2 number, since 2×21003143² = 882264031756898, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003173) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88130 + ... + 88367.

It is an arithmetic number, because the mean of its divisors is an integer number (3176964).

Almost surely, 2^21003143 is an apocalyptic number.

21003143 is a deficient number, since it is larger than the sum of its proper divisors (4412569).

21003143 is a wasteful number, since it uses less digits than its factorization.

21003143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176521.

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

The square root of 21003143 is about 4582.9186115400. The cubic root of 21003143 is about 275.9061809177.

Adding to 21003143 its reverse (34130012), we get a palindrome (55133155).

The spelling of 21003143 in words is "twenty-one million, three thousand, one hundred forty-three".