1979675921 has 2 divisors, whose sum is σ = 1979675922. Its totient is φ = 1979675920.

The previous prime is 1979675899. The next prime is 1979675933. The reversal of 1979675921 is 1295769791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1916250625 + 63425296 = 43775^2 + 7964^2 .

It is a cyclic number.

It is not a de Polignac number, because 1979675921 - 2¹⁰ = 1979674897 is a prime.

It is not a weakly prime, because it can be changed into another prime (1979672921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 989837960 + 989837961.

It is an arithmetic number, because the mean of its divisors is an integer number (989837961).

Almost surely, 2^1979675921 is an apocalyptic number.

It is an amenable number.

1979675921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1979675921 is an equidigital number, since it uses as much as digits as its factorization.

1979675921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2143260, while the sum is 56.

The square root of 1979675921 is about 44493.5492065985. The cubic root of 1979675921 is about 1255.6387220833.

The spelling of 1979675921 in words is "one billion, nine hundred seventy-nine million, six hundred seventy-five thousand, nine hundred twenty-one".