1921370791 has 2 divisors, whose sum is σ = 1921370792. Its totient is φ = 1921370790.

The previous prime is 1921370783. The next prime is 1921370797. The reversal of 1921370791 is 1970731291.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1921370791 - 2³ = 1921370783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1921370797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960685395 + 960685396.

It is an arithmetic number, because the mean of its divisors is an integer number (960685396).

Almost surely, 2^1921370791 is an apocalyptic number.

1921370791 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921370791 is an equidigital number, since it uses as much as digits as its factorization.

1921370791 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23814, while the sum is 40.

The square root of 1921370791 is about 43833.4437501778. The cubic root of 1921370791 is about 1243.1887213463.

The spelling of 1921370791 in words is "one billion, nine hundred twenty-one million, three hundred seventy thousand, seven hundred ninety-one".