1445521991 has 2 divisors, whose sum is σ = 1445521992. Its totient is φ = 1445521990.

The previous prime is 1445521969. The next prime is 1445522003. The reversal of 1445521991 is 1991255441.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1445521991 - 2²² = 1441327687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1445521901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 722760995 + 722760996.

It is an arithmetic number, because the mean of its divisors is an integer number (722760996).

Almost surely, 2^1445521991 is an apocalyptic number.

1445521991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1445521991 is an equidigital number, since it uses as much as digits as its factorization.

1445521991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 41.

The square root of 1445521991 is about 38020.0209231926. The cubic root of 1445521991 is about 1130.6848358703.

The spelling of 1445521991 in words is "one billion, four hundred forty-five million, five hundred twenty-one thousand, nine hundred ninety-one".