20717140 has 24 divisors (see below), whose sum is σ = 43829352. Its totient is φ = 8225280.

The previous prime is 20717131. The next prime is 20717141. The reversal of 20717140 is 4171702.

It can be written as a sum of positive squares in 4 ways, for example, as 1056784 + 19660356 = 1028^2 + 4434^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20717141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1041 + ... + 6520.

It is an arithmetic number, because the mean of its divisors is an integer number (1826223).

Almost surely, 2^20717140 is an apocalyptic number.

20717140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20717140 is an abundant number, since it is smaller than the sum of its proper divisors (23112212).

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

20717140 is a wasteful number, since it uses less digits than its factorization.

20717140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7707 (or 7705 counting only the distinct ones).

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 20717140 is about 4551.6085068907. The cubic root of 20717140 is about 274.6481008544.

Adding to 20717140 its reverse (4171702), we get a palindrome (24888842).

The spelling of 20717140 in words is "twenty million, seven hundred seventeen thousand, one hundred forty".