20757040 has 80 divisors (see below), whose sum is σ = 52228800. Its totient is φ = 7648256.

The previous prime is 20757031. The next prime is 20757043. The reversal of 20757040 is 4075702.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 20756996 and 20757014.

It is not an unprimeable number, because it can be changed into a prime (20757043) 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, 53166 + ... + 53554.

It is an arithmetic number, because the mean of its divisors is an integer number (652860).

Almost surely, 2^20757040 is an apocalyptic number.

20757040 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 20757040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26114400).

20757040 is an abundant number, since it is smaller than the sum of its proper divisors (31471760).

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

20757040 is a wasteful number, since it uses less digits than its factorization.

20757040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 448 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 25.

The square root of 20757040 is about 4555.9894644303. The cubic root of 20757040 is about 274.8243065087.

The spelling of 20757040 in words is "twenty million, seven hundred fifty-seven thousand, forty".