20720340 has 48 divisors (see below), whose sum is σ = 64464960. Its totient is φ = 5525280.

The previous prime is 20720327. The next prime is 20720341. The reversal of 20720340 is 4302702.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20720341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18646 + ... + 19725.

It is an arithmetic number, because the mean of its divisors is an integer number (1343020).

Almost surely, 2^20720340 is an apocalyptic number.

20720340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20720340 is an abundant number, since it is smaller than the sum of its proper divisors (43744620).

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

20720340 is a wasteful number, since it uses less digits than its factorization.

20720340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38389 (or 38381 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 18.

The square root of 20720340 is about 4551.9600173991. The cubic root of 20720340 is about 274.6622409766.

The spelling of 20720340 in words is "twenty million, seven hundred twenty thousand, three hundred forty".