1253555404021 has 4 divisors (see below), whose sum is σ = 1254203908492. Its totient is φ = 1252906899552.

The previous prime is 1253555403959. The next prime is 1253555404037. The reversal of 1253555404021 is 1204045553521.

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 508674209796 + 744881194225 = 713214^2 + 863065^2 .

It is a cyclic number.

It is not a de Polignac number, because 1253555404021 - 2³⁹ = 703799590133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1253555404061) 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, 324249336 + ... + 324253201.

It is an arithmetic number, because the mean of its divisors is an integer number (313550977123).

Almost surely, 2^{1253555404021} is an apocalyptic number.

It is an amenable number.

1253555404021 is a deficient number, since it is larger than the sum of its proper divisors (648504471).

1253555404021 is an equidigital number, since it uses as much as digits as its factorization.

1253555404021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648504470.

The product of its (nonzero) digits is 120000, while the sum is 37.

The spelling of 1253555404021 in words is "one trillion, two hundred fifty-three billion, five hundred fifty-five million, four hundred four thousand, twenty-one".