19947457 has 2 divisors, whose sum is σ = 19947458. Its totient is φ = 19947456.

The previous prime is 19947439. The next prime is 19947461. The reversal of 19947457 is 75474991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19678096 + 269361 = 4436^2 + 519^2 .

It is a cyclic number.

It is not a de Polignac number, because 19947457 - 2¹⁹ = 19423169 is a prime.

It is not a weakly prime, because it can be changed into another prime (19947407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9973728 + 9973729.

It is an arithmetic number, because the mean of its divisors is an integer number (9973729).

Almost surely, 2^19947457 is an apocalyptic number.

It is an amenable number.

19947457 is a deficient number, since it is larger than the sum of its proper divisors (1).

19947457 is an equidigital number, since it uses as much as digits as its factorization.

19947457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 317520, while the sum is 46.

The square root of 19947457 is about 4466.2576056470. The cubic root of 19947457 is about 271.2038471173.

The spelling of 19947457 in words is "nineteen million, nine hundred forty-seven thousand, four hundred fifty-seven".