1521661247 has 2 divisors, whose sum is σ = 1521661248. Its totient is φ = 1521661246.

The previous prime is 1521661201. The next prime is 1521661259. The reversal of 1521661247 is 7421661251.

It is a strong prime.

It is an emirp because it is prime and its reverse (7421661251) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1521661247 - 2⁸ = 1521660991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1521661147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 760830623 + 760830624.

It is an arithmetic number, because the mean of its divisors is an integer number (760830624).

Almost surely, 2^1521661247 is an apocalyptic number.

1521661247 is a deficient number, since it is larger than the sum of its proper divisors (1).

1521661247 is an equidigital number, since it uses as much as digits as its factorization.

1521661247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 35.

The square root of 1521661247 is about 39008.4766044510. The cubic root of 1521661247 is about 1150.1981377568.

The spelling of 1521661247 in words is "one billion, five hundred twenty-one million, six hundred sixty-one thousand, two hundred forty-seven".