921601861 has 2 divisors, whose sum is σ = 921601862. Its totient is φ = 921601860.

The previous prime is 921601819. The next prime is 921601921. The reversal of 921601861 is 168106129.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619711236 + 301890625 = 24894^2 + 17375^2 .

It is a cyclic number.

It is not a de Polignac number, because 921601861 - 2⁹ = 921601349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921601361) 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, 460800930 + 460800931.

It is an arithmetic number, because the mean of its divisors is an integer number (460800931).

Almost surely, 2^921601861 is an apocalyptic number.

It is an amenable number.

921601861 is a deficient number, since it is larger than the sum of its proper divisors (1).

921601861 is an equidigital number, since it uses as much as digits as its factorization.

921601861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 921601861 is about 30357.8961886360. The cubic root of 921601861 is about 973.1529743247.

The spelling of 921601861 in words is "nine hundred twenty-one million, six hundred one thousand, eight hundred sixty-one".