21031143 has 24 divisors (see below), whose sum is σ = 33050880. Its totient is φ = 11859120.

The previous prime is 21031111. The next prime is 21031151. The reversal of 21031143 is 34113012.

It is not a de Polignac number, because 21031143 - 2⁵ = 21031111 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031103) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10708 + ... + 12518.

It is an arithmetic number, because the mean of its divisors is an integer number (1377120).

Almost surely, 2^21031143 is an apocalyptic number.

21031143 is a deficient number, since it is larger than the sum of its proper divisors (12019737).

21031143 is a wasteful number, since it uses less digits than its factorization.

21031143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1907 (or 1900 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 21031143 is about 4585.9724159659. The cubic root of 21031143 is about 276.0287330935.

Adding to 21031143 its reverse (34113012), we get a palindrome (55144155).

The spelling of 21031143 in words is "twenty-one million, thirty-one thousand, one hundred forty-three".