1978620019 has 2 divisors, whose sum is σ = 1978620020. Its totient is φ = 1978620018.

The previous prime is 1978619989. The next prime is 1978620037. The reversal of 1978620019 is 9100268791.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1978620019 is a prime.

It is a super-2 number, since 2×1978620019² = 7829874359175120722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1978620079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989310009 + 989310010.

It is an arithmetic number, because the mean of its divisors is an integer number (989310010).

Almost surely, 2^1978620019 is an apocalyptic number.

1978620019 is a deficient number, since it is larger than the sum of its proper divisors (1).

1978620019 is an equidigital number, since it uses as much as digits as its factorization.

1978620019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 43.

The square root of 1978620019 is about 44481.6818364594. The cubic root of 1978620019 is about 1255.4154418966.

The spelling of 1978620019 in words is "one billion, nine hundred seventy-eight million, six hundred twenty thousand, nineteen".