21701971 has 16 divisors (see below), whose sum is σ = 23696640. Its totient is φ = 19807200.

The previous prime is 21701959. The next prime is 21701987. The reversal of 21701971 is 17910712.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21701971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21701941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82386 + ... + 82648.

It is an arithmetic number, because the mean of its divisors is an integer number (1481040).

Almost surely, 2^21701971 is an apocalyptic number.

21701971 is a deficient number, since it is larger than the sum of its proper divisors (1994669).

21701971 is a wasteful number, since it uses less digits than its factorization.

21701971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426.

The product of its (nonzero) digits is 882, while the sum is 28.

The square root of 21701971 is about 4658.5374314263. The cubic root of 21701971 is about 278.9328898252.

The spelling of 21701971 in words is "twenty-one million, seven hundred one thousand, nine hundred seventy-one".