1978363091 has 2 divisors, whose sum is σ = 1978363092. Its totient is φ = 1978363090.

The previous prime is 1978363073. The next prime is 1978363097. The reversal of 1978363091 is 1903638791.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1978363091 - 2¹⁴ = 1978346707 is a prime.

It is not a weakly prime, because it can be changed into another prime (1978363097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989181545 + 989181546.

It is an arithmetic number, because the mean of its divisors is an integer number (989181546).

Almost surely, 2^1978363091 is an apocalyptic number.

1978363091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978363091 is an equidigital number, since it uses as much as digits as its factorization.

1978363091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 1978363091 is about 44478.7937224021. The cubic root of 1978363091 is about 1255.3611000931.

The spelling of 1978363091 in words is "one billion, nine hundred seventy-eight million, three hundred sixty-three thousand, ninety-one".