21712351 has 8 divisors (see below), whose sum is σ = 22375440. Its totient is φ = 21058752.

The previous prime is 21712343. The next prime is 21712357. The reversal of 21712351 is 15321712.

It is a happy number.

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 21712351 - 2³ = 21712343 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 (21712357) 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, 2416 + ... + 7018.

It is an arithmetic number, because the mean of its divisors is an integer number (2796930).

Almost surely, 2^21712351 is an apocalyptic number.

21712351 is a deficient number, since it is larger than the sum of its proper divisors (663089).

21712351 is an equidigital number, since it uses as much as digits as its factorization.

21712351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4745.

The product of its digits is 420, while the sum is 22.

The square root of 21712351 is about 4659.6513818096. The cubic root of 21712351 is about 278.9773537114.

The spelling of 21712351 in words is "twenty-one million, seven hundred twelve thousand, three hundred fifty-one".