21712901 has 8 divisors (see below), whose sum is σ = 25155264. Its totient is φ = 18355680.

The previous prime is 21712871. The next prime is 21712907. The reversal of 21712901 is 10921712.

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

It is a de Polignac number, because none of the positive numbers 2^k-21712901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712907) 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, 20735 + ... + 21756.

It is an arithmetic number, because the mean of its divisors is an integer number (3144408).

Almost surely, 2^21712901 is an apocalyptic number.

It is an amenable number.

21712901 is a deficient number, since it is larger than the sum of its proper divisors (3442363).

21712901 is an equidigital number, since it uses as much as digits as its factorization.

21712901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42571.

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 21712901 is about 4659.7103987265. The cubic root of 21712901 is about 278.9797093023.

The spelling of 21712901 in words is "twenty-one million, seven hundred twelve thousand, nine hundred one".