20906340 has 144 divisors (see below), whose sum is σ = 73467072. Its totient is φ = 4402944.

The previous prime is 20906329. The next prime is 20906341. The reversal of 20906340 is 4360902.

It is a self number, because there is not a number n which added to its sum of digits gives 20906340.

It is not an unprimeable number, because it can be changed into a prime (20906341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 37947 + ... + 38493.

It is an arithmetic number, because the mean of its divisors is an integer number (510188).

Almost surely, 2^20906340 is an apocalyptic number.

20906340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20906340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36733536).

20906340 is an abundant number, since it is smaller than the sum of its proper divisors (52560732).

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

20906340 is a wasteful number, since it uses less digits than its factorization.

20906340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586 (or 577 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 20906340 is about 4572.3451313303. The cubic root of 20906340 is about 275.4816462905.

The spelling of 20906340 in words is "twenty million, nine hundred six thousand, three hundred forty".