21712073 has 8 divisors (see below), whose sum is σ = 22239360. Its totient is φ = 21187600.

The previous prime is 21712063. The next prime is 21712099. The reversal of 21712073 is 37021712.

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

It is not a de Polignac number, because 21712073 - 2⁴ = 21712057 is a prime.

It is a super-2 number, since 2×21712073² = 942828227914658, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21712063) 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, 30623 + ... + 31323.

It is an arithmetic number, because the mean of its divisors is an integer number (2779920).

Almost surely, 2^21712073 is an apocalyptic number.

It is an amenable number.

21712073 is a deficient number, since it is larger than the sum of its proper divisors (527287).

21712073 is an equidigital number, since it uses as much as digits as its factorization.

21712073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1407.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 21712073 is about 4659.6215511563. The cubic root of 21712073 is about 278.9761630522.

Adding to 21712073 its reverse (37021712), we get a palindrome (58733785).

The spelling of 21712073 in words is "twenty-one million, seven hundred twelve thousand, seventy-three".