1645961 has 2 divisors, whose sum is σ = 1645962. Its totient is φ = 1645960.

The previous prime is 1645939. The next prime is 1645967. The reversal of 1645961 is 1695461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1485961 + 160000 = 1219^2 + 400^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645961 is a prime.

It is a super-2 number, since 2×1645961² = 5418375227042, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1645967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822980 + 822981.

It is an arithmetic number, because the mean of its divisors is an integer number (822981).

2^1645961 is an apocalyptic number.

It is an amenable number.

1645961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645961 is an equidigital number, since it uses as much as digits as its factorization.

1645961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 1645961 is about 1282.9501159437. The cubic root of 1645961 is about 118.0700771146.

The spelling of 1645961 in words is "one million, six hundred forty-five thousand, nine hundred sixty-one".