21628143 has 6 divisors (see below), whose sum is σ = 31240664. Its totient is φ = 14418756.

The previous prime is 21628141. The next prime is 21628147. The reversal of 21628143 is 34182612.

21628143 is a `hidden beast` number, since 21 + 628 + 14 + 3 = 666.

It is not a de Polignac number, because 21628143 - 2¹ = 21628141 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 (21628141) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1201555 + ... + 1201572.

Almost surely, 2^21628143 is an apocalyptic number.

21628143 is a deficient number, since it is larger than the sum of its proper divisors (9612521).

21628143 is a wasteful number, since it uses less digits than its factorization.

21628143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2403133 (or 2403130 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21628143 is about 4650.6067346100. The cubic root of 21628143 is about 278.6162295936.

The spelling of 21628143 in words is "twenty-one million, six hundred twenty-eight thousand, one hundred forty-three".