21701571 has 8 divisors (see below), whose sum is σ = 30637584. Its totient is φ = 13616640.

The previous prime is 21701551. The next prime is 21701609. The reversal of 21701571 is 17510712.

It is a happy number.

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

It is not a de Polignac number, because 21701571 - 2¹³ = 21693379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21701531) 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, 212710 + ... + 212811.

It is an arithmetic number, because the mean of its divisors is an integer number (3829698).

Almost surely, 2^21701571 is an apocalyptic number.

21701571 is a deficient number, since it is larger than the sum of its proper divisors (8936013).

21701571 is a wasteful number, since it uses less digits than its factorization.

21701571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425541.

The product of its (nonzero) digits is 490, while the sum is 24.

The square root of 21701571 is about 4658.4944992991. The cubic root of 21701571 is about 278.9311760969.

It can be divided in two parts, 2170 and 1571, that added together give a triangular number (3741 = T₈₆).

The spelling of 21701571 in words is "twenty-one million, seven hundred one thousand, five hundred seventy-one".