21808702 has 4 divisors (see below), whose sum is σ = 32713056. Its totient is φ = 10904350.

The previous prime is 21808687. The next prime is 21808711. The reversal of 21808702 is 20780812.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5452174 + ... + 5452177.

It is an arithmetic number, because the mean of its divisors is an integer number (8178264).

Almost surely, 2^21808702 is an apocalyptic number.

21808702 is a deficient number, since it is larger than the sum of its proper divisors (10904354).

21808702 is a wasteful number, since it uses less digits than its factorization.

21808702 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10904353.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 21808702 is about 4669.9788008084. The cubic root of 21808702 is about 279.3894092600.

The spelling of 21808702 in words is "twenty-one million, eight hundred eight thousand, seven hundred two".