9781157 has 2 divisors, whose sum is σ = 9781158. Its totient is φ = 9781156.

The previous prime is 9781153. The next prime is 9781183. The reversal of 9781157 is 7511879.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8145316 + 1635841 = 2854^2 + 1279^2 .

It is a cyclic number.

It is not a de Polignac number, because 9781157 - 2² = 9781153 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 9781157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9781153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4890578 + 4890579.

It is an arithmetic number, because the mean of its divisors is an integer number (4890579).

Almost surely, 2^9781157 is an apocalyptic number.

It is an amenable number.

9781157 is a deficient number, since it is larger than the sum of its proper divisors (1).

9781157 is an equidigital number, since it uses as much as digits as its factorization.

9781157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17640, while the sum is 38.

The square root of 9781157 is about 3127.4841326536. The cubic root of 9781157 is about 213.8602531881.

The spelling of 9781157 in words is "nine million, seven hundred eighty-one thousand, one hundred fifty-seven".