20909340 has 60 divisors (see below), whose sum is σ = 65598456. Its totient is φ = 5575392.

The previous prime is 20909321. The next prime is 20909347. The reversal of 20909340 is 4390902.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20909347) 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 19 ways as a sum of consecutive naturals, for example, 4834 + ... + 8073.

Almost surely, 2^20909340 is an apocalyptic number.

20909340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20909340 is an abundant number, since it is smaller than the sum of its proper divisors (44689116).

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

20909340 is a wasteful number, since it uses less digits than its factorization.

20909340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12928 (or 12917 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 20909340 is about 4572.6731787872. The cubic root of 20909340 is about 275.4948226031.

The spelling of 20909340 in words is "twenty million, nine hundred nine thousand, three hundred forty".