921787157 has 2 divisors, whose sum is σ = 921787158. Its totient is φ = 921787156.

The previous prime is 921787117. The next prime is 921787193. The reversal of 921787157 is 751787129.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 723287236 + 198499921 = 26894^2 + 14089^2 .

It is an emirp because it is prime and its reverse (751787129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921787157 - 2⁶ = 921787093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921787117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460893578 + 460893579.

It is an arithmetic number, because the mean of its divisors is an integer number (460893579).

Almost surely, 2^921787157 is an apocalyptic number.

It is an amenable number.

921787157 is a deficient number, since it is larger than the sum of its proper divisors (1).

921787157 is an equidigital number, since it uses as much as digits as its factorization.

921787157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 246960, while the sum is 47.

The square root of 921787157 is about 30360.9478936347. The cubic root of 921787157 is about 973.2181902195.

The spelling of 921787157 in words is "nine hundred twenty-one million, seven hundred eighty-seven thousand, one hundred fifty-seven".