1645512061 has 2 divisors, whose sum is σ = 1645512062. Its totient is φ = 1645512060.

The previous prime is 1645512047. The next prime is 1645512073. The reversal of 1645512061 is 1602155461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1626589561 + 18922500 = 40331^2 + 4350^2 .

It is an emirp because it is prime and its reverse (1602155461) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645512061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645512031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822756030 + 822756031.

It is an arithmetic number, because the mean of its divisors is an integer number (822756031).

Almost surely, 2^1645512061 is an apocalyptic number.

It is an amenable number.

1645512061 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645512061 is an equidigital number, since it uses as much as digits as its factorization.

1645512061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 1645512061 is about 40564.9116971799. The cubic root of 1645512061 is about 1180.5934152565.

The spelling of 1645512061 in words is "one billion, six hundred forty-five million, five hundred twelve thousand, sixty-one".