21808074 has 8 divisors (see below), whose sum is σ = 43616160. Its totient is φ = 7269356.

The previous prime is 21808051. The next prime is 21808081. The reversal of 21808074 is 47080812.

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

21808074 is an admirable number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1817334 + ... + 1817345.

It is an arithmetic number, because the mean of its divisors is an integer number (5452020).

Almost surely, 2^21808074 is an apocalyptic number.

21808074 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21808074 is a wasteful number, since it uses less digits than its factorization.

21808074 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3634684.

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 21808074 is about 4669.9115623318. The cubic root of 21808074 is about 279.3867274829.

Adding to 21808074 its reverse (47080812), we get a palindrome (68888886).

The spelling of 21808074 in words is "twenty-one million, eight hundred eight thousand, seventy-four".