21716570 has 8 divisors (see below), whose sum is σ = 39089844. Its totient is φ = 8686624.

The previous prime is 21716567. The next prime is 21716573. The reversal of 21716570 is 7561712.

It is an interprime number because it is at equal distance from previous prime (21716567) and next prime (21716573).

It can be written as a sum of positive squares in 2 ways, for example, as 21520321 + 196249 = 4639^2 + 443^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21716573) 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, 1085819 + ... + 1085838.

Almost surely, 2^21716570 is an apocalyptic number.

21716570 is a deficient number, since it is larger than the sum of its proper divisors (17373274).

21716570 is a wasteful number, since it uses less digits than its factorization.

21716570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2171664.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 21716570 is about 4660.1040760910. The cubic root of 21716570 is about 278.9954222173.

The spelling of 21716570 in words is "twenty-one million, seven hundred sixteen thousand, five hundred seventy".