20808490 has 8 divisors (see below), whose sum is σ = 37455300. Its totient is φ = 8323392.

The previous prime is 20808481. The next prime is 20808497. The reversal of 20808490 is 9480802.

It can be written as a sum of positive squares in 2 ways, for example, as 18567481 + 2241009 = 4309^2 + 1497^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20808497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1040415 + ... + 1040434.

Almost surely, 2^20808490 is an apocalyptic number.

20808490 is a deficient number, since it is larger than the sum of its proper divisors (16646810).

20808490 is a wasteful number, since it uses less digits than its factorization.

20808490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2080856.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 20808490 is about 4561.6323832593. The cubic root of 20808490 is about 275.0511860644.

The spelling of 20808490 in words is "twenty million, eight hundred eight thousand, four hundred ninety".