20691210 has 64 divisors (see below), whose sum is σ = 54432000. Its totient is φ = 5010432.

The previous prime is 20691197. The next prime is 20691217. The reversal of 20691210 is 1219602.

It is not an unprimeable number, because it can be changed into a prime (20691217) by changing a digit.

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 in 31 ways as a sum of consecutive naturals, for example, 14091 + ... + 15489.

It is an arithmetic number, because the mean of its divisors is an integer number (850500).

Almost surely, 2^20691210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20691210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27216000).

20691210 is an abundant number, since it is smaller than the sum of its proper divisors (33740790).

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

20691210 is a wasteful number, since it uses less digits than its factorization.

20691210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1455.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 20691210 is about 4548.7591714664. The cubic root of 20691210 is about 274.5334679383.

The spelling of 20691210 in words is "twenty million, six hundred ninety-one thousand, two hundred ten".