Search a number
-
+
21690789 = 314235081
BaseRepresentation
bin101001010111…
…1100110100101
31111211000011120
41102233212211
521023101124
62052524153
7352240311
oct122574645
944730146
1021690789
111127567a
127320659
134655bb3
142c48b41
151d86d79
hex14af9a5

21690789 has 8 divisors (see below), whose sum is σ = 28947072. Its totient is φ = 14447520.

The previous prime is 21690787. The next prime is 21690803. The reversal of 21690789 is 98709612.

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

It is not a de Polignac number, because 21690789 - 21 = 21690787 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21690789.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690787) 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, 1729 + ... + 6809.

It is an arithmetic number, because the mean of its divisors is an integer number (3618384).

Almost surely, 221690789 is an apocalyptic number.

It is an amenable number.

21690789 is a deficient number, since it is larger than the sum of its proper divisors (7256283).

21690789 is a wasteful number, since it uses less digits than its factorization.

21690789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6507.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 21690789 is about 4657.3371147041. The cubic root of 21690789 is about 278.8849746162.

The spelling of 21690789 in words is "twenty-one million, six hundred ninety thousand, seven hundred eighty-nine".

Divisors: 1 3 1423 4269 5081 15243 7230263 21690789