1245401555221 has 16 divisors (see below), whose sum is σ = 1336885728048. Its totient is φ = 1155946291200.

The previous prime is 1245401555161. The next prime is 1245401555273. The reversal of 1245401555221 is 1225551045421.

It can be written as a sum of positive squares in 8 ways, for example, as 448211504196 + 797190051025 = 669486^2 + 892855^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1245401555221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1245401535221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11039661 + ... + 11151901.

It is an arithmetic number, because the mean of its divisors is an integer number (83555358003).

Almost surely, 2^{1245401555221} is an apocalyptic number.

It is an amenable number.

1245401555221 is a deficient number, since it is larger than the sum of its proper divisors (91484172827).

1245401555221 is a wasteful number, since it uses less digits than its factorization.

1245401555221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121272.

The product of its (nonzero) digits is 80000, while the sum is 37.

It can be divided in two parts, 124540 and 1555221, that added together give a palindrome (1679761).

The spelling of 1245401555221 in words is "one trillion, two hundred forty-five billion, four hundred one million, five hundred fifty-five thousand, two hundred twenty-one".