1721438687 has 2 divisors, whose sum is σ = 1721438688. Its totient is φ = 1721438686.

The previous prime is 1721438671. The next prime is 1721438731. The reversal of 1721438687 is 7868341271.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1721438687 - 2⁴ = 1721438671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721438617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860719343 + 860719344.

It is an arithmetic number, because the mean of its divisors is an integer number (860719344).

Almost surely, 2^1721438687 is an apocalyptic number.

1721438687 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721438687 is an equidigital number, since it uses as much as digits as its factorization.

1721438687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 47.

The square root of 1721438687 is about 41490.2239931288. The cubic root of 1721438687 is about 1198.4792511295.

The spelling of 1721438687 in words is "one billion, seven hundred twenty-one million, four hundred thirty-eight thousand, six hundred eighty-seven".