1646242861 has 2 divisors, whose sum is σ = 1646242862. Its totient is φ = 1646242860.

The previous prime is 1646242847. The next prime is 1646242883. The reversal of 1646242861 is 1682426461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 949810761 + 696432100 = 30819^2 + 26390^2 .

It is an emirp because it is prime and its reverse (1682426461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1646242861 - 2²⁷ = 1512025133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1646242891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 823121430 + 823121431.

It is an arithmetic number, because the mean of its divisors is an integer number (823121431).

Almost surely, 2^1646242861 is an apocalyptic number.

It is an amenable number.

1646242861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1646242861 is an equidigital number, since it uses as much as digits as its factorization.

1646242861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 40.

The square root of 1646242861 is about 40573.9184821974. The cubic root of 1646242861 is about 1180.7681632868.

The spelling of 1646242861 in words is "one billion, six hundred forty-six million, two hundred forty-two thousand, eight hundred sixty-one".