19491481 has 2 divisors, whose sum is σ = 19491482. Its totient is φ = 19491480.

The previous prime is 19491463. The next prime is 19491487. The reversal of 19491481 is 18419491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12250000 + 7241481 = 3500^2 + 2691^2 .

It is a cyclic number.

It is not a de Polignac number, because 19491481 - 2¹¹ = 19489433 is a prime.

It is a super-2 number, since 2×19491481² = 759835663146722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 19491481.

It is not a weakly prime, because it can be changed into another prime (19491487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9745740 + 9745741.

It is an arithmetic number, because the mean of its divisors is an integer number (9745741).

Almost surely, 2^19491481 is an apocalyptic number.

It is an amenable number.

19491481 is a deficient number, since it is larger than the sum of its proper divisors (1).

19491481 is an equidigital number, since it uses as much as digits as its factorization.

19491481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 37.

The square root of 19491481 is about 4414.9157409853. The cubic root of 19491481 is about 269.1214286658.

The spelling of 19491481 in words is "nineteen million, four hundred ninety-one thousand, four hundred eighty-one".