1445215991 has 2 divisors, whose sum is σ = 1445215992. Its totient is φ = 1445215990.

The previous prime is 1445215979. The next prime is 1445216051. The reversal of 1445215991 is 1995125441.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1445215991 - 2¹⁸ = 1444953847 is a prime.

It is a super-2 number, since 2×1445215991² = 4177298521284224162, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1445205991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 722607995 + 722607996.

It is an arithmetic number, because the mean of its divisors is an integer number (722607996).

Almost surely, 2^1445215991 is an apocalyptic number.

1445215991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1445215991 is an equidigital number, since it uses as much as digits as its factorization.

1445215991 is an evil number, because the sum of its binary digits is even.

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

The square root of 1445215991 is about 38015.9965146253. The cubic root of 1445215991 is about 1130.6050460138.

The spelling of 1445215991 in words is "one billion, four hundred forty-five million, two hundred fifteen thousand, nine hundred ninety-one".