1645890481 has 2 divisors, whose sum is σ = 1645890482. Its totient is φ = 1645890480.

The previous prime is 1645890473. The next prime is 1645890529. The reversal of 1645890481 is 1840985461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1369666081 + 276224400 = 37009^2 + 16620^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645890481 - 2³ = 1645890473 is a prime.

It is a super-2 number, since 2×1645890481² = 5417910950892822722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1645890401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822945240 + 822945241.

It is an arithmetic number, because the mean of its divisors is an integer number (822945241).

Almost surely, 2^1645890481 is an apocalyptic number.

It is an amenable number.

1645890481 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645890481 is an equidigital number, since it uses as much as digits as its factorization.

1645890481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 276480, while the sum is 46.

The square root of 1645890481 is about 40569.5758050291. The cubic root of 1645890481 is about 1180.6839090564.

The spelling of 1645890481 in words is "one billion, six hundred forty-five million, eight hundred ninety thousand, four hundred eighty-one".