21702143 has 8 divisors (see below), whose sum is σ = 22277376. Its totient is φ = 21130200.

The previous prime is 21702103. The next prime is 21702157. The reversal of 21702143 is 34120712.

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

It is a de Polignac number, because none of the positive numbers 2^k-21702143 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 (21702103) 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, 17948 + ... + 19118.

It is an arithmetic number, because the mean of its divisors is an integer number (2784672).

Almost surely, 2^21702143 is an apocalyptic number.

21702143 is a deficient number, since it is larger than the sum of its proper divisors (575233).

21702143 is a wasteful number, since it uses less digits than its factorization.

21702143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1645.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21702143 is about 4658.5558921194. Note that the first 3 decimals coincide. The cubic root of 21702143 is about 278.9336267218.

Adding to 21702143 its reverse (34120712), we get a palindrome (55822855).

The spelling of 21702143 in words is "twenty-one million, seven hundred two thousand, one hundred forty-three".