1517697421 has 2 divisors, whose sum is σ = 1517697422. Its totient is φ = 1517697420.

The previous prime is 1517697383. The next prime is 1517697439. The reversal of 1517697421 is 1247967151.

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., 1141764100 + 375933321 = 33790^2 + 19389^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1517697421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1517697121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 758848710 + 758848711.

It is an arithmetic number, because the mean of its divisors is an integer number (758848711).

Almost surely, 2^1517697421 is an apocalyptic number.

It is an amenable number.

1517697421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1517697421 is an equidigital number, since it uses as much as digits as its factorization.

1517697421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 105840, while the sum is 43.

The square root of 1517697421 is about 38957.6362347615. The cubic root of 1517697421 is about 1149.1985394948.

The spelling of 1517697421 in words is "one billion, five hundred seventeen million, six hundred ninety-seven thousand, four hundred twenty-one".