20897790 has 32 divisors (see below), whose sum is σ = 50280480. Its totient is φ = 5558784.

The previous prime is 20897761. The next prime is 20897801. The reversal of 20897790 is 9779802.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17946 + ... + 19074.

It is an arithmetic number, because the mean of its divisors is an integer number (1571265).

Almost surely, 2^20897790 is an apocalyptic number.

20897790 is an abundant number, since it is smaller than the sum of its proper divisors (29382690).

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

20897790 is a wasteful number, since it uses less digits than its factorization.

20897790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1756.

The product of its (nonzero) digits is 63504, while the sum is 42.

The square root of 20897790 is about 4571.4100669268. The cubic root of 20897790 is about 275.4440868829. Note that the first 3 decimals are identical.

The spelling of 20897790 in words is "twenty million, eight hundred ninety-seven thousand, seven hundred ninety".