1680492521 has 2 divisors, whose sum is σ = 1680492522. Its totient is φ = 1680492520.

The previous prime is 1680492481. The next prime is 1680492533. The reversal of 1680492521 is 1252940861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1563095296 + 117397225 = 39536^2 + 10835^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1680492521 is a prime.

It is a super-2 number, since 2×1680492521² = 5648110226273870882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1680492581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840246260 + 840246261.

It is an arithmetic number, because the mean of its divisors is an integer number (840246261).

Almost surely, 2^1680492521 is an apocalyptic number.

It is an amenable number.

1680492521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680492521 is an equidigital number, since it uses as much as digits as its factorization.

1680492521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 1680492521 is about 40993.8107645532. The cubic root of 1680492521 is about 1188.9005500902.

The spelling of 1680492521 in words is "one billion, six hundred eighty million, four hundred ninety-two thousand, five hundred twenty-one".