921157609 has 2 divisors, whose sum is σ = 921157610. Its totient is φ = 921157608.

The previous prime is 921157579. The next prime is 921157637. The reversal of 921157609 is 906751129.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 913731984 + 7425625 = 30228^2 + 2725^2 .

It is an emirp because it is prime and its reverse (906751129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921157609 - 2⁵ = 921157577 is a prime.

It is not a weakly prime, because it can be changed into another prime (921157669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460578804 + 460578805.

It is an arithmetic number, because the mean of its divisors is an integer number (460578805).

Almost surely, 2^921157609 is an apocalyptic number.

It is an amenable number.

921157609 is a deficient number, since it is larger than the sum of its proper divisors (1).

921157609 is an equidigital number, since it uses as much as digits as its factorization.

921157609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020, while the sum is 40.

The square root of 921157609 is about 30350.5783964655. The cubic root of 921157609 is about 972.9965819032.

The spelling of 921157609 in words is "nine hundred twenty-one million, one hundred fifty-seven thousand, six hundred nine".