1646899979 has 2 divisors, whose sum is σ = 1646899980. Its totient is φ = 1646899978.

The previous prime is 1646899963. The next prime is 1646900011. The reversal of 1646899979 is 9799986461.

It is a weak prime.

It is an emirp because it is prime and its reverse (9799986461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1646899979 - 2⁴ = 1646899963 is a prime.

It is not a weakly prime, because it can be changed into another prime (1646899909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 823449989 + 823449990.

It is an arithmetic number, because the mean of its divisors is an integer number (823449990).

Almost surely, 2^1646899979 is an apocalyptic number.

1646899979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1646899979 is an equidigital number, since it uses as much as digits as its factorization.

1646899979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52907904, while the sum is 68.

The square root of 1646899979 is about 40582.0154625174. The cubic root of 1646899979 is about 1180.9252484124.

The spelling of 1646899979 in words is "one billion, six hundred forty-six million, eight hundred ninety-nine thousand, nine hundred seventy-nine".