20731340 has 48 divisors (see below), whose sum is σ = 50014272. Its totient is φ = 7070976.

The previous prime is 20731339. The next prime is 20731351. The reversal of 20731340 is 4313702.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 52022 + ... + 52418.

It is an arithmetic number, because the mean of its divisors is an integer number (1041964).

Almost surely, 2^20731340 is an apocalyptic number.

20731340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20731340 is an abundant number, since it is smaller than the sum of its proper divisors (29282932).

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

20731340 is a wasteful number, since it uses less digits than its factorization.

20731340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 786 (or 784 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 20731340 is about 4553.1681277985. The cubic root of 20731340 is about 274.7108365461.

The spelling of 20731340 in words is "twenty million, seven hundred thirty-one thousand, three hundred forty".