20715137 has 4 divisors (see below), whose sum is σ = 20998980. Its totient is φ = 20431296.

The previous prime is 20715113. The next prime is 20715169. The reversal of 20715137 is 73151702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4036081 + 16679056 = 2009^2 + 4084^2 .

It is a cyclic number.

It is not a de Polignac number, because 20715137 - 2²⁰ = 19666561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20715337) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141812 + ... + 141957.

It is an arithmetic number, because the mean of its divisors is an integer number (5249745).

Almost surely, 2^20715137 is an apocalyptic number.

It is an amenable number.

20715137 is a deficient number, since it is larger than the sum of its proper divisors (283843).

20715137 is an equidigital number, since it uses as much as digits as its factorization.

20715137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283842.

The product of its (nonzero) digits is 1470, while the sum is 26.

The square root of 20715137 is about 4551.3884694673. The cubic root of 20715137 is about 274.6392492807.

Adding to 20715137 its reverse (73151702), we get a palindrome (93866839).

The spelling of 20715137 in words is "twenty million, seven hundred fifteen thousand, one hundred thirty-seven".