921978361 has 2 divisors, whose sum is σ = 921978362. Its totient is φ = 921978360.

The previous prime is 921978349. The next prime is 921978373. The reversal of 921978361 is 163879129.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (921978349) and next prime (921978373).

It can be written as a sum of positive squares in only one way, i.e., 900300025 + 21678336 = 30005^2 + 4656^2 .

It is an emirp because it is prime and its reverse (163879129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921978361 - 2⁵ = 921978329 is a prime.

It is not a weakly prime, because it can be changed into another prime (921978311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460989180 + 460989181.

It is an arithmetic number, because the mean of its divisors is an integer number (460989181).

Almost surely, 2^921978361 is an apocalyptic number.

It is an amenable number.

921978361 is a deficient number, since it is larger than the sum of its proper divisors (1).

921978361 is an equidigital number, since it uses as much as digits as its factorization.

921978361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 46.

The square root of 921978361 is about 30364.0965780311. The cubic root of 921978361 is about 973.2854763041.

The spelling of 921978361 in words is "nine hundred twenty-one million, nine hundred seventy-eight thousand, three hundred sixty-one".