21670505 has 8 divisors (see below), whose sum is σ = 26057472. Its totient is φ = 17301168.

The previous prime is 21670501. The next prime is 21670513. The reversal of 21670505 is 50507612.

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 21670505 - 2² = 21670501 is a prime.

It is a super-2 number, since 2×21670505² = 939221573910050, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21670501) 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, 1529 + ... + 6758.

It is an arithmetic number, because the mean of its divisors is an integer number (3257184).

Almost surely, 2^21670505 is an apocalyptic number.

It is an amenable number.

21670505 is a deficient number, since it is larger than the sum of its proper divisors (4386967).

21670505 is an equidigital number, since it uses as much as digits as its factorization.

21670505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8815.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 21670505 is about 4655.1589661364. The cubic root of 21670505 is about 278.7980150151.

The spelling of 21670505 in words is "twenty-one million, six hundred seventy thousand, five hundred five".