1845647521 has 3 divisors (see below), whose sum is σ = 1845690483. Its totient is φ = 1845604560.

The previous prime is 1845647497. The next prime is 1845647597. The reversal of 1845647521 is 1257465481.

The square root of 1845647521 is 42961.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1257465481 = 127 ⋅9901303.

It can be written as a sum of positive squares in only one way, i.e., 200533921 + 1645113600 = 14161^2 + 40560^2 .

It is not a de Polignac number, because 1845647521 - 2²¹ = 1843550369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1845677521) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 21481 + ... + 64441.

It is an arithmetic number, because the mean of its divisors is an integer number (615230161).

Almost surely, 2^1845647521 is an apocalyptic number.

1845647521 is the 42961-st square number.

1845647521 is the 21481-st centered octagonal number.

It is an amenable number.

1845647521 is a deficient number, since it is larger than the sum of its proper divisors (42962).

1845647521 is an frugal number, since it uses more digits than its factorization.

1845647521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85922 (or 42961 counting only the distinct ones).

The product of its digits is 268800, while the sum is 43.

The cubic root of 1845647521 is about 1226.6375481020.

The spelling of 1845647521 in words is "one billion, eight hundred forty-five million, six hundred forty-seven thousand, five hundred twenty-one".