1851240523609 has 9 divisors (see below), whose sum is σ = 1891532004607. Its totient is φ = 1811789839624.

The previous prime is 1851240523603. The next prime is 1851240523621. The reversal of 1851240523609 is 9063250421581.

The square root of 1851240523609 is 1360603.

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

It can be written as a sum of positive squares in only one way, i.e., 1838727864009 + 12512659600 = 1355997^2 + 111860^2 .

It is not a de Polignac number, because 1851240523609 - 2³¹ = 1849093039961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1851240523603) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 63933867 + ... + 63962815.

Almost surely, 2^{1851240523609} is an apocalyptic number.

1851240523609 is the 1360603-rd square number.

1851240523609 is the 680302-nd centered octagonal number.

It is an amenable number.

1851240523609 is a deficient number, since it is larger than the sum of its proper divisors (40291480998).

1851240523609 is an frugal number, since it uses more digits than its factorization.

1851240523609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57992 (or 28996 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 46.

The spelling of 1851240523609 in words is "one trillion, eight hundred fifty-one billion, two hundred forty million, five hundred twenty-three thousand, six hundred nine".