21971771 has 8 divisors (see below), whose sum is σ = 23259600. Its totient is φ = 20697120.

The previous prime is 21971749. The next prime is 21971783. The reversal of 21971771 is 17717912.

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 21971771 - 2⁶ = 21971707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21971711) 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, 245 + ... + 6633.

It is an arithmetic number, because the mean of its divisors is an integer number (2907450).

Almost surely, 2^21971771 is an apocalyptic number.

21971771 is a deficient number, since it is larger than the sum of its proper divisors (1287829).

21971771 is a wasteful number, since it uses less digits than its factorization.

21971771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6589.

The product of its digits is 6174, while the sum is 35.

The square root of 21971771 is about 4687.4055723822. The cubic root of 21971771 is about 280.0840351505.

The spelling of 21971771 in words is "twenty-one million, nine hundred seventy-one thousand, seven hundred seventy-one".