21670369 has 8 divisors (see below), whose sum is σ = 24871680. Its totient is φ = 18495456.

The previous prime is 21670339. The next prime is 21670373. The reversal of 21670369 is 96307612.

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

It is not a de Polignac number, because 21670369 - 2²¹ = 19573217 is a prime.

It is a super-2 number, since 2×21670369² = 939209785192322, 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 (21670309) 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, 4804 + ... + 8149.

It is an arithmetic number, because the mean of its divisors is an integer number (3108960).

Almost surely, 2^21670369 is an apocalyptic number.

It is an amenable number.

21670369 is a deficient number, since it is larger than the sum of its proper divisors (3201311).

21670369 is a wasteful number, since it uses less digits than its factorization.

21670369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13199.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 21670369 is about 4655.1443586639. The cubic root of 21670369 is about 278.7974317860.

The spelling of 21670369 in words is "twenty-one million, six hundred seventy thousand, three hundred sixty-nine".