1245805021009 has 4 divisors (see below), whose sum is σ = 1247504619316. Its totient is φ = 1244105422704.

The previous prime is 1245805020949. The next prime is 1245805021039. The reversal of 1245805021009 is 9001205085421.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1092344793409 + 153460227600 = 1045153^2 + 391740^2 .

It is a cyclic number.

It is not a de Polignac number, because 1245805021009 - 2¹⁷ = 1245804889937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1245805021039) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 849798054 + ... + 849799519.

It is an arithmetic number, because the mean of its divisors is an integer number (311876154829).

Almost surely, 2^{1245805021009} is an apocalyptic number.

It is an amenable number.

1245805021009 is a deficient number, since it is larger than the sum of its proper divisors (1699598307).

1245805021009 is an equidigital number, since it uses as much as digits as its factorization.

1245805021009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1699598306.

The product of its (nonzero) digits is 28800, while the sum is 37.

The spelling of 1245805021009 in words is "one trillion, two hundred forty-five billion, eight hundred five million, twenty-one thousand, nine".