21717701 has 4 divisors (see below), whose sum is σ = 22418304. Its totient is φ = 21017100.

The previous prime is 21717679. The next prime is 21717737. The reversal of 21717701 is 10771712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21717701 - 2⁶ = 21717637 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 (21717791) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 350255 + ... + 350316.

It is an arithmetic number, because the mean of its divisors is an integer number (5604576).

Almost surely, 2^21717701 is an apocalyptic number.

It is an amenable number.

21717701 is a deficient number, since it is larger than the sum of its proper divisors (700603).

21717701 is an equidigital number, since it uses as much as digits as its factorization.

21717701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700602.

The product of its (nonzero) digits is 686, while the sum is 26.

The square root of 21717701 is about 4660.2254237322. The cubic root of 21717701 is about 279.0002654982. Note that the first 3 decimals are identical.

The spelling of 21717701 in words is "twenty-one million, seven hundred seventeen thousand, seven hundred one".