21500143 has 8 divisors (see below), whose sum is σ = 25364480. Its totient is φ = 17834040.

The previous prime is 21500137. The next prime is 21500161. The reversal of 21500143 is 34100512.

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

It is not a de Polignac number, because 21500143 - 2⁵ = 21500111 is a prime.

It is a super-2 number, since 2×21500143² = 924512298040898, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49323 + ... + 49756.

It is an arithmetic number, because the mean of its divisors is an integer number (3170560).

Almost surely, 2^21500143 is an apocalyptic number.

21500143 is a deficient number, since it is larger than the sum of its proper divisors (3864337).

21500143 is an equidigital number, since it uses as much as digits as its factorization.

21500143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99117.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21500143 is about 4636.8246678088. The cubic root of 21500143 is about 278.0655048096.

Adding to 21500143 its reverse (34100512), we get a palindrome (55600655).

The spelling of 21500143 in words is "twenty-one million, five hundred thousand, one hundred forty-three".