21751071 has 8 divisors (see below), whose sum is σ = 29110320. Its totient is φ = 14446272.

The previous prime is 21751069. The next prime is 21751087. The reversal of 21751071 is 17015712.

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 21751071 - 2¹ = 21751069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21751021) 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, 12670 + ... + 14283.

It is an arithmetic number, because the mean of its divisors is an integer number (3638790).

Almost surely, 2^21751071 is an apocalyptic number.

21751071 is a deficient number, since it is larger than the sum of its proper divisors (7359249).

21751071 is a wasteful number, since it uses less digits than its factorization.

21751071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27225.

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

The square root of 21751071 is about 4663.8043483834. The cubic root of 21751071 is about 279.1430902294.

Adding to 21751071 its reverse (17015712), we get a palindrome (38766783).

The spelling of 21751071 in words is "twenty-one million, seven hundred fifty-one thousand, seventy-one".