21920308 has 6 divisors (see below), whose sum is σ = 38360546. Its totient is φ = 10960152.

The previous prime is 21920299. The next prime is 21920321. The reversal of 21920308 is 80302912.

It can be written as a sum of positive squares in only one way, i.e., 20412324 + 1507984 = 4518^2 + 1228^2 .

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, 2740035 + ... + 2740042.

Almost surely, 2^21920308 is an apocalyptic number.

It is an amenable number.

21920308 is a deficient number, since it is larger than the sum of its proper divisors (16440238).

21920308 is a wasteful number, since it uses less digits than its factorization.

21920308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5480081 (or 5480079 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21920308 is about 4681.9128569421. The cubic root of 21920308 is about 279.8651902065.

The spelling of 21920308 in words is "twenty-one million, nine hundred twenty thousand, three hundred eight".