21700143 has 42 divisors (see below), whose sum is σ = 34897304. Its totient is φ = 13483584.

The previous prime is 21700127. The next prime is 21700169. The reversal of 21700143 is 34100712.

It is not a de Polignac number, because 21700143 - 2⁴ = 21700127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21700103) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 210630 + ... + 210732.

Almost surely, 2^21700143 is an apocalyptic number.

21700143 is a deficient number, since it is larger than the sum of its proper divisors (13197161).

21700143 is an equidigital number, since it uses as much as digits as its factorization.

21700143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21700143 is about 4658.3412283773. The cubic root of 21700143 is about 278.9250579153.

Adding to 21700143 its reverse (34100712), we get a palindrome (55800855).

The spelling of 21700143 in words is "twenty-one million, seven hundred thousand, one hundred forty-three".