21025143 has 8 divisors (see below), whose sum is σ = 31148400. Its totient is φ = 14016744.

The previous prime is 21025129. The next prime is 21025157. The reversal of 21025143 is 34152012.

It is an interprime number because it is at equal distance from previous prime (21025129) and next prime (21025157).

It is not a de Polignac number, because 21025143 - 2⁴ = 21025127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21025163) 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, 389328 + ... + 389381.

It is an arithmetic number, because the mean of its divisors is an integer number (3893550).

Almost surely, 2^21025143 is an apocalyptic number.

21025143 is a deficient number, since it is larger than the sum of its proper divisors (10123257).

21025143 is an equidigital number, since it uses as much as digits as its factorization.

21025143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778718 (or 778712 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21025143 is about 4585.3182005178. The cubic root of 21025143 is about 276.0024810741.

Adding to 21025143 its reverse (34152012), we get a palindrome (55177155).

The spelling of 21025143 in words is "twenty-one million, twenty-five thousand, one hundred forty-three".