1445555621 has 2 divisors, whose sum is σ = 1445555622. Its totient is φ = 1445555620.

The previous prime is 1445555603. The next prime is 1445555623. The reversal of 1445555621 is 1265555441.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1060218721 + 385336900 = 32561^2 + 19630^2 .

It is a cyclic number.

It is not a de Polignac number, because 1445555621 - 2¹⁸ = 1445293477 is a prime.

Together with 1445555623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1445555623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 722777810 + 722777811.

It is an arithmetic number, because the mean of its divisors is an integer number (722777811).

Almost surely, 2^1445555621 is an apocalyptic number.

It is an amenable number.

1445555621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1445555621 is an equidigital number, since it uses as much as digits as its factorization.

1445555621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120000, while the sum is 38.

The square root of 1445555621 is about 38020.4631876046. The cubic root of 1445555621 is about 1130.6936042452.

The spelling of 1445555621 in words is "one billion, four hundred forty-five million, five hundred fifty-five thousand, six hundred twenty-one".