1721415681 has 6 divisors (see below), whose sum is σ = 2486489330. Its totient is φ = 1147610448.

The previous prime is 1721415677. The next prime is 1721415721. The reversal of 1721415681 is 1865141271.

It can be written as a sum of positive squares in only one way, i.e., 1671501456 + 49914225 = 40884^2 + 7065^2 .

It is not a de Polignac number, because 1721415681 - 2² = 1721415677 is a prime.

It is a super-2 number, since 2×1721415681² = 5926543893585387522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1721415281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 95634196 + ... + 95634213.

Almost surely, 2^1721415681 is an apocalyptic number.

It is an amenable number.

1721415681 is a deficient number, since it is larger than the sum of its proper divisors (765073649).

1721415681 is a wasteful number, since it uses less digits than its factorization.

1721415681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191268415 (or 191268412 counting only the distinct ones).

The product of its digits is 13440, while the sum is 36.

The square root of 1721415681 is about 41489.9467461697. The cubic root of 1721415681 is about 1198.4739121192.

The spelling of 1721415681 in words is "one billion, seven hundred twenty-one million, four hundred fifteen thousand, six hundred eighty-one".