20307157 has 4 divisors (see below), whose sum is σ = 21869260. Its totient is φ = 18745056.

The previous prime is 20307121. The next prime is 20307179. The reversal of 20307157 is 75170302.

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 11029041 + 9278116 = 3321^2 + 3046^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20307157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20307107) 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, 781032 + ... + 781057.

It is an arithmetic number, because the mean of its divisors is an integer number (5467315).

Almost surely, 2^20307157 is an apocalyptic number.

It is an amenable number.

20307157 is a deficient number, since it is larger than the sum of its proper divisors (1562103).

20307157 is a wasteful number, since it uses less digits than its factorization.

20307157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1562102.

The product of its (nonzero) digits is 1470, while the sum is 25.

The square root of 20307157 is about 4506.3463027158. The cubic root of 20307157 is about 272.8242953354.

Adding to 20307157 its reverse (75170302), we get a palindrome (95477459).

The spelling of 20307157 in words is "twenty million, three hundred seven thousand, one hundred fifty-seven".