1680148721 has 2 divisors, whose sum is σ = 1680148722. Its totient is φ = 1680148720.

The previous prime is 1680148703. The next prime is 1680148741. The reversal of 1680148721 is 1278410861.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 921972496 + 758176225 = 30364^2 + 27535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1680148721 is a prime.

It is not a weakly prime, because it can be changed into another prime (1680148741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840074360 + 840074361.

It is an arithmetic number, because the mean of its divisors is an integer number (840074361).

Almost surely, 2^1680148721 is an apocalyptic number.

It is an amenable number.

1680148721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680148721 is an equidigital number, since it uses as much as digits as its factorization.

1680148721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21504, while the sum is 38.

The square root of 1680148721 is about 40989.6172341241. The cubic root of 1680148721 is about 1188.8194683278.

The spelling of 1680148721 in words is "one billion, six hundred eighty million, one hundred forty-eight thousand, seven hundred twenty-one".