21143971 has 8 divisors (see below), whose sum is σ = 22455360. Its totient is φ = 19840128.

The previous prime is 21143951. The next prime is 21143977. The reversal of 21143971 is 17934112.

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

It is a cyclic number.

It is not a de Polignac number, because 21143971 - 2⁹ = 21143459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21143977) 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, 4545 + ... + 7933.

It is an arithmetic number, because the mean of its divisors is an integer number (2806920).

Almost surely, 2^21143971 is an apocalyptic number.

21143971 is a deficient number, since it is larger than the sum of its proper divisors (1311389).

21143971 is a wasteful number, since it uses less digits than its factorization.

21143971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3773.

The product of its digits is 1512, while the sum is 28.

The square root of 21143971 is about 4598.2573873153. The cubic root of 21143971 is about 276.5214665265.

The spelling of 21143971 in words is "twenty-one million, one hundred forty-three thousand, nine hundred seventy-one".