1991485453 has 2 divisors, whose sum is σ = 1991485454. Its totient is φ = 1991485452.

The previous prime is 1991485423. The next prime is 1991485471. The reversal of 1991485453 is 3545841991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1486719364 + 504766089 = 38558^2 + 22467^2 .

It is a cyclic number.

It is not a de Polignac number, because 1991485453 - 2²¹ = 1989388301 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1991485397 and 1991485406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1991485403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995742726 + 995742727.

It is an arithmetic number, because the mean of its divisors is an integer number (995742727).

Almost surely, 2^1991485453 is an apocalyptic number.

It is an amenable number.

1991485453 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991485453 is an equidigital number, since it uses as much as digits as its factorization.

1991485453 is an evil number, because the sum of its binary digits is even.

The product of its digits is 777600, while the sum is 49.

The square root of 1991485453 is about 44626.0624859510. The cubic root of 1991485453 is about 1258.1305637903.

The spelling of 1991485453 in words is "one billion, nine hundred ninety-one million, four hundred eighty-five thousand, four hundred fifty-three".