1721408929 has 2 divisors, whose sum is σ = 1721408930. Its totient is φ = 1721408928.

The previous prime is 1721408813. The next prime is 1721408963. The reversal of 1721408929 is 9298041271.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1712718225 + 8690704 = 41385^2 + 2948^2 .

It is an emirp because it is prime and its reverse (9298041271) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1721408929 is a prime.

It is not a weakly prime, because it can be changed into another prime (1721408989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860704464 + 860704465.

It is an arithmetic number, because the mean of its divisors is an integer number (860704465).

Almost surely, 2^1721408929 is an apocalyptic number.

It is an amenable number.

1721408929 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721408929 is an equidigital number, since it uses as much as digits as its factorization.

1721408929 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 1721408929 is about 41489.8653769809. The cubic root of 1721408929 is about 1198.4723451712.

The spelling of 1721408929 in words is "one billion, seven hundred twenty-one million, four hundred eight thousand, nine hundred twenty-nine".